The mouth of the Housatonic River and the stretch of Long Island Sound immediately to the east and west is one of the richest natural spawning areas for oysters not only in the Sound but probably in the northeast.
Oysters that spawn in the Housatonic populate the mouth of the river, and currents sweep oyster larvae around Stratford Point, where they settle out on Bridgeport Natural Bed, a four-square mile area from Point No Point to Black Rock that is so important to the Sound’s oystermen that state regulators allow oyster boats to use hand-powered dredges only, so as not to damage the beds with power dredges.
I visited Stratford Point today to learn about Connecticut Audubon Society’s habitat restoration project there, and in the course of an hour’s conversation with Scott Kruitbosch, Connecticut Audubon’s conservation technician, some interesting speculation about the Housatonic oyster beds emerged.
Last year at this time, Scott told me, there were “massive” numbers of diving ducks on the mouth of the river. Greater and Lesser Scaup. White-winged Scoters and Surf Scoters, maybe Black Scoters, as well as Redheads and King Eider.
This year, nothing. The protected cove to the north has plenty of dabblers -- American Wigeon, Black Ducks, Gadwall -- but the diving ducks are not around.
The diet of diving ducks includes small oysters. The speculation by Connecticut Audubon’s conservation staff -- a guess, really -- is that something happened to the oyster beds. And the further speculation is that what happened was Hurricane Irene.
Numerous oystermen reported in September that the storm had damaged their equipment and smothered their oyster beds with sand and mud. Historically, the infamous hurricane of 1938 did so much damage -- wrecking oyster boats and oyster beds -- that it almost wiped out the Sound’s oyster industry. It took two decades for it to recover.
I haven’t seen a full assessment of the damage that Irene did to the Sound’s oysters. But if the lack of diving ducks on the Housatonic is an indication, the damage includes not only the Sound’s oystermen but possibly the wildlife that relies on the Sound’s oysters as well.
You can read more about Stratford Point here and here on Connecticut Audubon's website. -- Tom Andersen
Tuesday, December 13, 2011
Monday, December 12, 2011
8,041 Broad-winged Hawks
I have greatly enjoyed many of the days spent hawk watching thus far in three seasons at Boothe Memorial Park in Stratford, though I do not think any surpassed the thrill of September 16, 2011, when 8,234 raptors were recorded including 8,041 Broad-winged Hawks. Contrary to the prelude to the day in my last writing on the historic Turkey Vulture flight, I felt extremely certain that we were about to be enthralled by a flight of thousands of Broad-winged Hawks in the week leading up to it. Even a full six days before the flight we were set to receive I was mentioning it to friends and fellow observers, saying in an email that a fast and strong cold front would be “hard to time…exactly a week away but it'll be fun, mega Broad-wing push”. Boothe’s previous Broad-winged Hawk daily record was only 1,884, this was only year three, and I am not a psychic – what made me so confident about that day?
I went back and examined some of the "mega" flights at various points in Connecticut's history in the year since the conclusion of the 2010 hawk watch season in an effort to determine when one would occur again. Thanks to Neil Currie and so many other vigilant hawk watchers over the last 40 years we have a very strong set of data that can guide you to general flight dates. The late teens of September are a superb time for Broad-winged Hawks to fly, and this has become generally basic knowledge among those invested in the hobby. Knowing when a given species has the itch to get on the move to the south is one very important factor, but what happens if the weather doesn’t cooperate? Some birds, especially the Broad-winged Hawk, would never want to move against a southerly wind or under particularly overcast and rainy skies.
Atmospheric success
I put on my weather hat and dove in to meteorological data, using the dates of some of the biggest flights of Broad-winged Hawks the region had ever seen and examining the weather conditions that made them possible. I looked for patterns in the atmosphere on a large scale – wind speed and direction, the placement of high pressure centers, any blocking weather in the days before, sky conditions, temperatures and precipitation, and more. Some of the major motivating factors fell in line with conventional hawk watch wisdom, namely that raptors often take to the skies after the passage of a fall cold front. However, this is where things get much more complicated as a simple frontal passage is not sufficient for a strong hawk movement, let alone a historic one.
The most important factor, in my eyes, is the recent placement of a strong high pressure center over the vicinity of the Great Lakes region during the daytime hours of a given flight day. Such a perfect placement is seen infrequently with a cold air mass filtering down from Canada in the wake of a low in September. For the most part, the cold front passage has to be swift enough and clean, without any other areas of low pressure remaining nearby, without the presence of residual precipitation via a subsequent shortwave or other means, and sizable enough to encompass at least the entire northeastern United States and southeastern Canada. This seems to be the best conveyor belt for Broad-winged Hawks, pushing them to the south across multiple states, and such a placement puts Connecticut squarely under northwest winds from the anti-cyclonic flow of the high. The timing of the movement of the high is important for the flight but also for the pressure gradient as the winds have to be light to moderate, as a howling wind from the northwest will move some birds, but not allow thousands to stream through.
There are actually many more ways a passing cold front could permit a small or moderate flight, though not a sizable one. Let’s say a cold front passes through with high pressure moving in from the south – this flow will be westerly and ultimately southwesterly, disallowing any substantial movement whatsoever. We could have a weak cold front passing through with showers followed by a lack of any significant air mass, or an upper trough causing completely overcast skies (limiting thermals) and some precipitation on its heels. Sometimes a cold front will pass through only to stall out just to the east or southeast of Connecticut, making it difficult to get raptors moving through our air in any great numbers. Sometimes you do not need a cold front at all, and one of the best periods of movement in 2011 proved that. The departure of a sluggish upper level low spinning over the region in early October was followed by a high that graced us with light northwest winds on October 5 and 6, pushing through 352 and 621 raptors, respectively, with October 6 allowing Boothe to break daily Sharp-shinned Hawk and Bald Eagle records, among others.
September 2011’s weather
The key to a massive Broad-winged Hawk flight is clearly the weather leading up to and on the day in question, and this held true in 2011. Early September was plagued by a nearly constant southerly or southwest flow in the wake of Tropical Storm Irene. The few fronts that passed through Connecticut stalled near or over the region, with one coming through in the first week of September stopping off our coast as Hurricane Katia came north through the Atlantic. Her sizable influence and cyclonic flow actually provided the best hawk watching day for Boothe Park prior to this Broad-winged Hawk flight, with 40 raptors seen under light northwest winds – yes, only forty. It is abundantly clear that the hawks were stopped from any significant movement whatsoever prior to the date of the major flight this September, and it is likely this contributed to the extremely large movement that followed.
Once we were around one week away, I noticed that long-range models indicated the likely possibility of a large and strong cold front stretching from southeast Canada to the Gulf coast pushing through late in the following week, clearing the entire eastern seaboard. A strong high pressure center would move through the northern Great Plains and possibly settle near the Great Lakes or Ohio Valley. This is essentially what occurred with wondrously fortuitous timing as the front cleared well off the Atlantic coast overnight on September 15, allowing for the air mass of the high to take over as it moved in to position near the Great Lakes near sunrise. The distance between pressure centers was enough to keep the winds at a moderate strength, around 8-12 MPH at our site, with occasional gusts lessening in frequency and intensity as the day went along. We were even able to muster up some light cirrus overhead to top off the near-ideal conditions.
Boothe Park’s position
A lot has been said about the position of Boothe Memorial Park in discussions about the high number of raptors occasionally passing over. It is situated approximately three miles off Long Island Sound from its closest point, actually in Milford. Somewhat like Turkey Vultures and some of the other buteo species, huge numbers of Broad-winged Hawks are reluctant to move much closer to the coast than our position, and indeed, many that come over are heading to the west or west southwest rather than south or even southwest. We can have streams of birds in a long train heading west while more are being added to it by incoming kettles from the north. Below is a shot of us on September 16, unfortunately the only photo taken that day during the nonstop action, counting the streams of Broad-wings going to the west southwest.
Once again, like the Turkey Vultures, the key at Boothe Park is to have a light to moderate wind from the north or northwest. Any easterly component pushes birds away from us due to geography, and when it comes to Broad-winged Hawks, they will not take to the sky in nearly the same force. As I discussed in the above section, the winds were mostly light to moderate, with occasionally stronger gusts that wore down as the day progressed. This ensured that the Broad-wings would be pushed from all inland areas down along the coast, but not so much that they were battered in the air, kept from attaining the appropriate altitude, or forced to fly to our south.
Nine exhilarating hours
The count began at 8:00 a.m., with Bill Banks joining me bright and early. We would remain there for the next nine hours, with Charlie Barnard and Frank Mantlik spending significant portions of the heavy afternoon flight there, and Penny Solum joining us for some time in the morning. As most hawk watchers know, it takes some time for raptors to get into the skies mostly because of the fact they are waiting for thermals, rising columns of warm air that help them almost effortlessly glide to the south. This is particularly true at Boothe Park for another reason as it is difficult to see much around ground level because of trees, buildings, and other impediments. The birds have to be relatively high in the sky to see them, and we typically only get early birds either directly over our heads or in gaps to the east and southeast near the Housatonic River.
We tallied a few quick Bald Eagles, Ospreys, Cooper’s Hawks, a bunch of Sharp-shinned Hawks, a Northern Harrier, and an American Kestrel. In the case of Broad-winged Hawks, it takes them an especially long time to wake up and get on the move, and we did not have any of them until 18 passed through between 10:00 and 11:00 a.m. By this point, I was beginning to get a little anxious about my prediction, and whether or not we would be able to pull off a large enough flight in approximately the next four or five hours. Catching even a couple thousand birds in such a time frame seemed like an insurmountable task at the rate we were going, but I kept repeating to myself (in my head and out loud, as others can likely attest to) that this was a perfect setup on a perfect date, and we were going to be paid off soon enough.
I suppose many of the Broad-winged Hawks we saw that day had some distance to cover after taking to the skies, moving to the south from other parts of Connecticut or coming in from nearby areas in the first few hours of the day before reaching us. Not long after 11 a.m. the major flight started, and before the hour was over, we had broken our hourly record of 876 birds (set on 09/20/10 by me, counting alone, from 3:00 to 4:00 p.m. that day) with a strong 892. Even if we maintained this rate we would have a tremendous afternoon, and we thought that if we could get a few more clouds than the 15% cover of cirrus we had that hour, this could be spectacular. Suffice it to say, we did, and it was more than we could have hoped for. We shattered the hourly record and the daily total record between 12:00 and 1:00 p.m. as we tallied 1,278 Broad-winged Hawks, pushing our total over 2,000.
I certainly did not anticipate doubling this over in the next hour, but from 1:00 to 2:00 p.m. we counted a mind-blowing 2,887 passing over our heads. For the most part this took the form of an exceptionally long and seemingly endless river of raptors nearly directly above our position, slightly to the north of straight up from the site. It spanned the sky from the trees and neighborhoods to the west all the way to the horizon over the Housatonic in the east. We craned our necks until we could not bear the physical pain any longer, the four of us trying to somehow keep track of and count every single bird in this enormous river. Part of the problem I recall having was that they flew in a wide track stretching beyond one or even two binocular views, especially tough for my “10s”.
One had to sweep their binoculars back and forth simply to count all the birds in even one small section of the river all while they moved to the west. Bill, Charlie, and Frank were fantastic, calling out the numbers to me as I added them up in my head and occasionally scratched down totals on the data sheet. We all tried to count these overwhelming numbers as best we could while keeping on the conservative side if we ever lost track of a few, being careful not to double count any. Our independent counts of sometimes hundreds of birds were often extremely close to one another. A few times we had to stop and stare in awe, being overwhelmed by the sheer outrageousness and splendor of the sight, unable to think correctly or process it fully. I thought we would be able to cruise past 3,000 in the hour, but they started to slow down from their peak movement before we got to 3 o’clock.
That is not to say the movement was anything but astonishing in the next hour as we totaled more 2,468 Broad-winged Hawks. Our bodies would finally get a respite from constantly staring upwards as the flight rapidly slowed down before 4:00 p.m., and we concluded at 5:00 after a final hour of 175 more. Here are the unreal totals for the raptor migrants tallied during our nine hours of observation:
Osprey - 30
Bald Eagle - 11
Northern Harrier - 5
Sharp-shinned Hawk - 122
Cooper's Hawk - 12
Broad-winged Hawk - 8,041
American Kestrel - 12
Un. Buteo - 1
TOTAL - 8,234
Broad-winged Hawk flight history
I had some idea of the magnitude of our total in that it was of limited historic nature, though that it was nowhere near the top days seen in Connecticut, as some flights have been over 10,000 birds, with Quaker Ridge in Greenwich having a couple of days over 30,000. I surely thought the other coastal sites that day, Quaker or Lighthouse Point in New Haven, would have numbers similar to ours, probably greater at the former and lesser at the latter. However, the conditions I described apparently did play out perfectly for us, as we beat the more-inland Greenwich total of 6,342 raptors, 6,176 being Broad-winged Hawks. Lighthouse Point, being right on the water, had 3,713 raptors with 3,116 Broads, having had more of the other species, also to be expected.
Neil Currie, one of the founders of the NorthEast Hawk Watch and raptor migration expert, has been a force in creating and promoting hawk watching for 40 years. It is because of him and others that we have all of the information on migration that we do now, from prime locations to observe raptors, to the dates of flights, and decades of data. Neil was kind enough to compile and send me information on the largest flights of Broad-winged Hawks ever in Connecticut so that I could get a sense of the significance of this flight and compare it further to when others like it occurred. All of the data discussed below does not yet include the 2011 season.
There have been 456 days in which over 1,000 hawks were observed at a given location in Connecticut, with 2,000+ being seen 192 times, 3,000+ recorded 99 times, 4,000+ tallied 67 times, and a sensational total of 5,000+ on 47 occasions. All of the dates of the sightings of 5,000+ raptors fall between September 12 and 25, with the majority being between the September 14 and 19. Unsurprisingly, Quaker Ridge leads the pack with 14 of these days, followed by a tie for second of four each for Lighthouse Point and Whippoorwill Hill, out of 20 different sites. In consideration to our total of 8,234 at Boothe Park on September 16, there had been 19 previous counts of 8,000+ hawks in Connecticut history, this being the 20th in the last 40 years.
On the surface, this leads one to think such an event happens every other year, but this is not the case. Some of the mammoth flights have been recorded at multiple locations on the same day at these extreme levels, such as a movement on September 19, 1993 that featured 25,307 raptors at Booth Hill in West Hartland, 23,371 at Woodchuck Lane in Harwinton, and 22,475 at Quaker Ridge in Greenwich. Some have occurred back to back, like a flight of 30,786 raptors at Quaker Ridge followed two days later by a movement of 10,022 more at Greenwich Point. Interestingly, 24 of the flights over 5,000 took place in the 1980s, and 19 took place in the 1990s, with only three being recorded in the first decade of the 21st century.
As far as I can tell, the 8,234 raptors we recorded at Boothe Park on September 16, 2011 was the highest one-day total seen in Connecticut since 11,107 were counted at Booth Hill in West Hartland on September 13, 1998, when I would have been just shy of 13 years-old and quite clueless as to the very existence of such phenomena possibly occurring down the road from me at Boothe Park. That is an extraordinarily remarkable time period, and only makes the observations and memories of that day even more special. Let us hope that more days like this are coming in the future, and the population of Broad-winged Hawks to our north did not peak in the past. I cannot wait to see what September 2012 has in store for us and if we will be able to predict it so accurately once again.
You can see more information, from directions to all of this data, on our HawkCount page here:
http://www.hawkcount.org/siteinfo.php?rsite=703
Looks like a good day for hawks! (See the weather vane at the top of the tower in this northwest facing photo by Frank Mantlik)
I went back and examined some of the "mega" flights at various points in Connecticut's history in the year since the conclusion of the 2010 hawk watch season in an effort to determine when one would occur again. Thanks to Neil Currie and so many other vigilant hawk watchers over the last 40 years we have a very strong set of data that can guide you to general flight dates. The late teens of September are a superb time for Broad-winged Hawks to fly, and this has become generally basic knowledge among those invested in the hobby. Knowing when a given species has the itch to get on the move to the south is one very important factor, but what happens if the weather doesn’t cooperate? Some birds, especially the Broad-winged Hawk, would never want to move against a southerly wind or under particularly overcast and rainy skies.
Atmospheric success
I put on my weather hat and dove in to meteorological data, using the dates of some of the biggest flights of Broad-winged Hawks the region had ever seen and examining the weather conditions that made them possible. I looked for patterns in the atmosphere on a large scale – wind speed and direction, the placement of high pressure centers, any blocking weather in the days before, sky conditions, temperatures and precipitation, and more. Some of the major motivating factors fell in line with conventional hawk watch wisdom, namely that raptors often take to the skies after the passage of a fall cold front. However, this is where things get much more complicated as a simple frontal passage is not sufficient for a strong hawk movement, let alone a historic one.
The most important factor, in my eyes, is the recent placement of a strong high pressure center over the vicinity of the Great Lakes region during the daytime hours of a given flight day. Such a perfect placement is seen infrequently with a cold air mass filtering down from Canada in the wake of a low in September. For the most part, the cold front passage has to be swift enough and clean, without any other areas of low pressure remaining nearby, without the presence of residual precipitation via a subsequent shortwave or other means, and sizable enough to encompass at least the entire northeastern United States and southeastern Canada. This seems to be the best conveyor belt for Broad-winged Hawks, pushing them to the south across multiple states, and such a placement puts Connecticut squarely under northwest winds from the anti-cyclonic flow of the high. The timing of the movement of the high is important for the flight but also for the pressure gradient as the winds have to be light to moderate, as a howling wind from the northwest will move some birds, but not allow thousands to stream through.
There are actually many more ways a passing cold front could permit a small or moderate flight, though not a sizable one. Let’s say a cold front passes through with high pressure moving in from the south – this flow will be westerly and ultimately southwesterly, disallowing any substantial movement whatsoever. We could have a weak cold front passing through with showers followed by a lack of any significant air mass, or an upper trough causing completely overcast skies (limiting thermals) and some precipitation on its heels. Sometimes a cold front will pass through only to stall out just to the east or southeast of Connecticut, making it difficult to get raptors moving through our air in any great numbers. Sometimes you do not need a cold front at all, and one of the best periods of movement in 2011 proved that. The departure of a sluggish upper level low spinning over the region in early October was followed by a high that graced us with light northwest winds on October 5 and 6, pushing through 352 and 621 raptors, respectively, with October 6 allowing Boothe to break daily Sharp-shinned Hawk and Bald Eagle records, among others.
September 2011’s weather
The key to a massive Broad-winged Hawk flight is clearly the weather leading up to and on the day in question, and this held true in 2011. Early September was plagued by a nearly constant southerly or southwest flow in the wake of Tropical Storm Irene. The few fronts that passed through Connecticut stalled near or over the region, with one coming through in the first week of September stopping off our coast as Hurricane Katia came north through the Atlantic. Her sizable influence and cyclonic flow actually provided the best hawk watching day for Boothe Park prior to this Broad-winged Hawk flight, with 40 raptors seen under light northwest winds – yes, only forty. It is abundantly clear that the hawks were stopped from any significant movement whatsoever prior to the date of the major flight this September, and it is likely this contributed to the extremely large movement that followed.
Once we were around one week away, I noticed that long-range models indicated the likely possibility of a large and strong cold front stretching from southeast Canada to the Gulf coast pushing through late in the following week, clearing the entire eastern seaboard. A strong high pressure center would move through the northern Great Plains and possibly settle near the Great Lakes or Ohio Valley. This is essentially what occurred with wondrously fortuitous timing as the front cleared well off the Atlantic coast overnight on September 15, allowing for the air mass of the high to take over as it moved in to position near the Great Lakes near sunrise. The distance between pressure centers was enough to keep the winds at a moderate strength, around 8-12 MPH at our site, with occasional gusts lessening in frequency and intensity as the day went along. We were even able to muster up some light cirrus overhead to top off the near-ideal conditions.
Boothe Park’s position
A lot has been said about the position of Boothe Memorial Park in discussions about the high number of raptors occasionally passing over. It is situated approximately three miles off Long Island Sound from its closest point, actually in Milford. Somewhat like Turkey Vultures and some of the other buteo species, huge numbers of Broad-winged Hawks are reluctant to move much closer to the coast than our position, and indeed, many that come over are heading to the west or west southwest rather than south or even southwest. We can have streams of birds in a long train heading west while more are being added to it by incoming kettles from the north. Below is a shot of us on September 16, unfortunately the only photo taken that day during the nonstop action, counting the streams of Broad-wings going to the west southwest.
From left to right, Charlie Barnard, the clipboard on the chair, Scott Kruitbosch, Bill Banks - taken by Frank Mantlik
Once again, like the Turkey Vultures, the key at Boothe Park is to have a light to moderate wind from the north or northwest. Any easterly component pushes birds away from us due to geography, and when it comes to Broad-winged Hawks, they will not take to the sky in nearly the same force. As I discussed in the above section, the winds were mostly light to moderate, with occasionally stronger gusts that wore down as the day progressed. This ensured that the Broad-wings would be pushed from all inland areas down along the coast, but not so much that they were battered in the air, kept from attaining the appropriate altitude, or forced to fly to our south.
Nine exhilarating hours
The count began at 8:00 a.m., with Bill Banks joining me bright and early. We would remain there for the next nine hours, with Charlie Barnard and Frank Mantlik spending significant portions of the heavy afternoon flight there, and Penny Solum joining us for some time in the morning. As most hawk watchers know, it takes some time for raptors to get into the skies mostly because of the fact they are waiting for thermals, rising columns of warm air that help them almost effortlessly glide to the south. This is particularly true at Boothe Park for another reason as it is difficult to see much around ground level because of trees, buildings, and other impediments. The birds have to be relatively high in the sky to see them, and we typically only get early birds either directly over our heads or in gaps to the east and southeast near the Housatonic River.
We tallied a few quick Bald Eagles, Ospreys, Cooper’s Hawks, a bunch of Sharp-shinned Hawks, a Northern Harrier, and an American Kestrel. In the case of Broad-winged Hawks, it takes them an especially long time to wake up and get on the move, and we did not have any of them until 18 passed through between 10:00 and 11:00 a.m. By this point, I was beginning to get a little anxious about my prediction, and whether or not we would be able to pull off a large enough flight in approximately the next four or five hours. Catching even a couple thousand birds in such a time frame seemed like an insurmountable task at the rate we were going, but I kept repeating to myself (in my head and out loud, as others can likely attest to) that this was a perfect setup on a perfect date, and we were going to be paid off soon enough.
I suppose many of the Broad-winged Hawks we saw that day had some distance to cover after taking to the skies, moving to the south from other parts of Connecticut or coming in from nearby areas in the first few hours of the day before reaching us. Not long after 11 a.m. the major flight started, and before the hour was over, we had broken our hourly record of 876 birds (set on 09/20/10 by me, counting alone, from 3:00 to 4:00 p.m. that day) with a strong 892. Even if we maintained this rate we would have a tremendous afternoon, and we thought that if we could get a few more clouds than the 15% cover of cirrus we had that hour, this could be spectacular. Suffice it to say, we did, and it was more than we could have hoped for. We shattered the hourly record and the daily total record between 12:00 and 1:00 p.m. as we tallied 1,278 Broad-winged Hawks, pushing our total over 2,000.
I certainly did not anticipate doubling this over in the next hour, but from 1:00 to 2:00 p.m. we counted a mind-blowing 2,887 passing over our heads. For the most part this took the form of an exceptionally long and seemingly endless river of raptors nearly directly above our position, slightly to the north of straight up from the site. It spanned the sky from the trees and neighborhoods to the west all the way to the horizon over the Housatonic in the east. We craned our necks until we could not bear the physical pain any longer, the four of us trying to somehow keep track of and count every single bird in this enormous river. Part of the problem I recall having was that they flew in a wide track stretching beyond one or even two binocular views, especially tough for my “10s”.
One had to sweep their binoculars back and forth simply to count all the birds in even one small section of the river all while they moved to the west. Bill, Charlie, and Frank were fantastic, calling out the numbers to me as I added them up in my head and occasionally scratched down totals on the data sheet. We all tried to count these overwhelming numbers as best we could while keeping on the conservative side if we ever lost track of a few, being careful not to double count any. Our independent counts of sometimes hundreds of birds were often extremely close to one another. A few times we had to stop and stare in awe, being overwhelmed by the sheer outrageousness and splendor of the sight, unable to think correctly or process it fully. I thought we would be able to cruise past 3,000 in the hour, but they started to slow down from their peak movement before we got to 3 o’clock.
That is not to say the movement was anything but astonishing in the next hour as we totaled more 2,468 Broad-winged Hawks. Our bodies would finally get a respite from constantly staring upwards as the flight rapidly slowed down before 4:00 p.m., and we concluded at 5:00 after a final hour of 175 more. Here are the unreal totals for the raptor migrants tallied during our nine hours of observation:
Osprey - 30
Bald Eagle - 11
Northern Harrier - 5
Sharp-shinned Hawk - 122
Cooper's Hawk - 12
Broad-winged Hawk - 8,041
American Kestrel - 12
Un. Buteo - 1
TOTAL - 8,234
Broad-winged Hawk flight history
I had some idea of the magnitude of our total in that it was of limited historic nature, though that it was nowhere near the top days seen in Connecticut, as some flights have been over 10,000 birds, with Quaker Ridge in Greenwich having a couple of days over 30,000. I surely thought the other coastal sites that day, Quaker or Lighthouse Point in New Haven, would have numbers similar to ours, probably greater at the former and lesser at the latter. However, the conditions I described apparently did play out perfectly for us, as we beat the more-inland Greenwich total of 6,342 raptors, 6,176 being Broad-winged Hawks. Lighthouse Point, being right on the water, had 3,713 raptors with 3,116 Broads, having had more of the other species, also to be expected.
Neil Currie, one of the founders of the NorthEast Hawk Watch and raptor migration expert, has been a force in creating and promoting hawk watching for 40 years. It is because of him and others that we have all of the information on migration that we do now, from prime locations to observe raptors, to the dates of flights, and decades of data. Neil was kind enough to compile and send me information on the largest flights of Broad-winged Hawks ever in Connecticut so that I could get a sense of the significance of this flight and compare it further to when others like it occurred. All of the data discussed below does not yet include the 2011 season.
There have been 456 days in which over 1,000 hawks were observed at a given location in Connecticut, with 2,000+ being seen 192 times, 3,000+ recorded 99 times, 4,000+ tallied 67 times, and a sensational total of 5,000+ on 47 occasions. All of the dates of the sightings of 5,000+ raptors fall between September 12 and 25, with the majority being between the September 14 and 19. Unsurprisingly, Quaker Ridge leads the pack with 14 of these days, followed by a tie for second of four each for Lighthouse Point and Whippoorwill Hill, out of 20 different sites. In consideration to our total of 8,234 at Boothe Park on September 16, there had been 19 previous counts of 8,000+ hawks in Connecticut history, this being the 20th in the last 40 years.
On the surface, this leads one to think such an event happens every other year, but this is not the case. Some of the mammoth flights have been recorded at multiple locations on the same day at these extreme levels, such as a movement on September 19, 1993 that featured 25,307 raptors at Booth Hill in West Hartland, 23,371 at Woodchuck Lane in Harwinton, and 22,475 at Quaker Ridge in Greenwich. Some have occurred back to back, like a flight of 30,786 raptors at Quaker Ridge followed two days later by a movement of 10,022 more at Greenwich Point. Interestingly, 24 of the flights over 5,000 took place in the 1980s, and 19 took place in the 1990s, with only three being recorded in the first decade of the 21st century.
As far as I can tell, the 8,234 raptors we recorded at Boothe Park on September 16, 2011 was the highest one-day total seen in Connecticut since 11,107 were counted at Booth Hill in West Hartland on September 13, 1998, when I would have been just shy of 13 years-old and quite clueless as to the very existence of such phenomena possibly occurring down the road from me at Boothe Park. That is an extraordinarily remarkable time period, and only makes the observations and memories of that day even more special. Let us hope that more days like this are coming in the future, and the population of Broad-winged Hawks to our north did not peak in the past. I cannot wait to see what September 2012 has in store for us and if we will be able to predict it so accurately once again.
You can see more information, from directions to all of this data, on our HawkCount page here:
http://www.hawkcount.org/siteinfo.php?rsite=703
Scott Kruitbosch
Conservation Technician
Conservation Technician
Photos © Frank Mantlik
Saturday, December 10, 2011
Migratory bats
I wanted to bring up the subject of bats after some sightings that I have had in the past few weeks. On November 26, I noticed a unique flying creature swirling around through my neighborhood around sunset. It was quickly obvious that it was not a swallow or a swift. I was able to determine that it was a Red Bat (Lasiurus borealis), a species of Special Concern on the Connecticut Endangered Species Act, before it flew off to the south continuing its migration as darkness overtook the area. Red Bats are forest dwellers, and while it was certainly not out of place in my neighborhood, it did seem late in the season for a sighting.
Little is known about the migratory routes and timing of departure from Connecticut or points north for the various bat species we can expect to see in our state, but November and December can be brutally cold months for insectivores. Even October was a perilous month this year. Stratford Point is actually a good place to spot Red Bats in the fall, and we are starting to think the site may be on a migration route with bats following either the Housatonic River to the south or the Long Island Sound coastline to the west. An extreme example occurred on the morning after Tropical Storm Irene. I arrived at Stratford Point well before sunrise, and around 6 a.m. I spotted a Red Bat coming in from Long Island Sound and heading towards our main building, likely roosting there, possibly in the vents along the roof, for the day. I believe it was returning to land after finding itself over water as the sun came up, as many birds do.
Again, the Red Bat is a forest dwelling species, and the mouth of the Housatonic River, sands of Long Island Sound, and Stratford Point's coastal grasslands are well out of place for it. Inclement weather likely pushes some of the others to stay here and hunt the area, once again just like some bird species that are out of habitat on the property do. Another notable sighting was of a bat species flying into the gable vent on the main building of Stratford Point on Tuesday afternoon, December 6, as the rain poured down and fog continued to cover the area. Twan believes what I saw was an Eastern Pipistrelle (Pipistrellus subflavus) as we have already encountered the species on the property in December before, with a single Eastern Pipistrelle seen roosting in a building during an extreme cold snap a couple years ago. We do not know if it was a migrant or a resident.
I also had a recent report via an at-reply to our Twitter account of what an observer believes to be multiple Little Brown Bats every night in their yard. Clearly, there is a lot to learn about bats in Connecticut, and we would always appreciate hearing about any sightings you have, especially during the fall and winter months.
Scott Kruitbosch
Conservation Technician
Little is known about the migratory routes and timing of departure from Connecticut or points north for the various bat species we can expect to see in our state, but November and December can be brutally cold months for insectivores. Even October was a perilous month this year. Stratford Point is actually a good place to spot Red Bats in the fall, and we are starting to think the site may be on a migration route with bats following either the Housatonic River to the south or the Long Island Sound coastline to the west. An extreme example occurred on the morning after Tropical Storm Irene. I arrived at Stratford Point well before sunrise, and around 6 a.m. I spotted a Red Bat coming in from Long Island Sound and heading towards our main building, likely roosting there, possibly in the vents along the roof, for the day. I believe it was returning to land after finding itself over water as the sun came up, as many birds do.
Again, the Red Bat is a forest dwelling species, and the mouth of the Housatonic River, sands of Long Island Sound, and Stratford Point's coastal grasslands are well out of place for it. Inclement weather likely pushes some of the others to stay here and hunt the area, once again just like some bird species that are out of habitat on the property do. Another notable sighting was of a bat species flying into the gable vent on the main building of Stratford Point on Tuesday afternoon, December 6, as the rain poured down and fog continued to cover the area. Twan believes what I saw was an Eastern Pipistrelle (Pipistrellus subflavus) as we have already encountered the species on the property in December before, with a single Eastern Pipistrelle seen roosting in a building during an extreme cold snap a couple years ago. We do not know if it was a migrant or a resident.
I also had a recent report via an at-reply to our Twitter account of what an observer believes to be multiple Little Brown Bats every night in their yard. Clearly, there is a lot to learn about bats in Connecticut, and we would always appreciate hearing about any sightings you have, especially during the fall and winter months.
Scott Kruitbosch
Conservation Technician
Wednesday, December 7, 2011
Historic Turkey Vulture Flight
The Boothe Park Hawk Watch has now closed for the 2011 season with a sensational 12,215 raptors counted in only 115.5 hours. This is the first of a series of pieces that I, as the coordinator of the site who spent the vast majority of those hours there, will be writing during the offseason on some of the special sightings and notable numbers we enjoyed this year.
On October 28, 2011, the hawk watch at Boothe Memorial Park in Stratford experienced an unprecedented event as those on hand tallied 521 migrant Turkey Vultures in only 7.5 hours of observation, obliterating any known flight record in New England and even some beyond. This astounding total was supplemented by 218 Red-tailed Hawks, a sum not to be relegated to an afterthought. The Red-tail count is believed to be the third highest in New England history, falling short of a Lighthouse Point total of 237 on November 7, 1999, and Boothe’s own total of 249 on November 1, 2010, the current record holder. Not coincidentally and as will be examined, that day held Boothe’s previous Turkey Vulture high count of 190, also one of the best ever in the northeast. In only the third year of opportunistic observation, Boothe has established itself as a regional force to be reckoned with when it comes to buteos and vultures, and a strong site for nearly every other Connecticut migrant raptor species.
Comparisons
It is safe to say that no one could have predicted the enormity of the Turkey Vulture explosion of October 28 as such a sum has traditionally been reserved for an elite group of watch sites with decades of experience. Many of these sites are far to our south, like Kiptopeke in Virginia, or buoyed with supreme geographical aids, as is the case in Cape May each fall or Braddock Bay in the spring. Cape May was one of my first thoughts at the conclusion of the epic day – specifically, had we come even close to touching one of their best flight days for Turkey Vultures? One has to bear in mind that they hold records that the vast majority of count sites can never dream of impinging upon. Seeing 1,023 Osprey or 278 Northern Harrier in one day is laughable for us here in Connecticut, but still not as impossibly insurmountable as daily totals of 7,000 Sharp-shinned Hawk or 1,231 Cooper’s Hawk are. For now, I can only dream that Boothe Park will complete an entire season with those sorts of numbers in the not too distant future.
Cape May’s top three Turkey Vulture flights are “only” 784, 607, and 602, still comfortably beyond the 521 we witnessed on October 28, but not at all embarrassing in comparison to Boothe’s new record. This immediately invigorated me, and I looked at many other sites in New England and the Mid-Atlantic, finding few if any that came even close to this spectacular fall flight. I already knew that Connecticut’s two major sites, Quaker Ridge in Greenwich and Lighthouse Point, in a combined total of over 80 years of observations, were nowhere close to our new record. Their top flights were 192 and 135, respectively. Moving out of state to a couple of other infamous sites, Franklin Mountain in New York topped off at 136 Turkey Vultures and Hawk Mountain Sanctuary in Pennsylvania peaked at 123, and several more locations were around these numbers. I should add one condition to these decades and decades of observations - the Turkey Vulture population is increasing to our north over time, and it must be understood that more migrants will be passing through, generally, every year. Regardless of that fact, Boothe’s total remains almost supreme amongst many similar and strong opponents.
The day’s weather
After that examination, the most obvious question remained: why did such an extremely high number of Turkey Vultures take to the skies to head south on this particular day? October 28 is in a range of time quite conducive to significant flights, though it is still relatively early in the season, with the last Boothe record occurring four days later the previous year, and the instant conclusion being that the date did not act like a late trigger to suddenly spur the birds south. One would presume beforehand that they would have kept migrating in a regular manner for another few weeks at the very least. I have already discussed the lack of totals approaching this one at other sites, thus for the moment making the small sample size of Boothe’s data somewhat less of a confounding variable, and this flight more of an anomaly. For the sake of argument, let us assume it was - that leaves us to wonder what exactly that trigger was and what in the world could have prompted this.
What remains is the weather, the conditions on and around this special day that helped to allow such an event to take place that Friday morning. The Tuesday before, October 25, had actually been a very productive day at Boothe Park with 276 raptors tallied, 76 of them Turkey Vultures, despite crystal clear blue skies. This flight in itself provides evidence that there were not birds being “backed up” by poor conditions for a week or more, and many had been able to move through Connecticut already. If there had been only a few raptors counted in the days before, or a continual southerly flow of some sort, a subsequent record flight might have been more understandable. That Tuesday movement came after a cold front passed through from a low centered well to the north in Canada and on northwest winds from high pressure moving through the Ohio Valley.
On that Wednesday and Thursday, October 26 and 27, the northeast region was plagued by a series of lows along a cold front that finally passed through Thursday night. As that front swiftly cleared our area and headed southeast, one of the biggest keys to the event came in the form of a superbly placed high moving in from the Great Lakes towards western New York and Pennsylvania just in time for the daytime hours on Friday. The pressure gradient was not very strong because of the rapid exodus of the front, and the high provided northwest winds of approximately 4-7 MPH for most of the day on Friday, a perfect strength to aid raptors moving south and gently push them to follow the coastline, but not thrust them all the way to the shore. This wind speed and direction has been shown to be optimal for Boothe Park on numerous occasions with it being a few miles off Long Island Sound.
2010 flight conditions
These conditions were, not coincidentally, nearly indistinguishable to the ones that provided the terrific flight at Boothe Park previously mentioned on November 1, 2010. The movement of the cold front, the placement of the high, wind speed and direction were all essentially the same, though there had been no cloud cover whatsoever that day. Turkey Vultures do sometimes fly by Boothe Park at high altitudes, though most go through at a moderate height compared to other species, and nearly all are detectable to the naked eye or binoculars even against the deep blue sky with their dark color and slow drifting style. Even when streaming through they often come in groups, thus the likelihood of missing a significant amount because of a lack of clouds, or finding more because of even partial cloud cover, is negligible.
Typical streaming Turkey Vultures at Boothe Park
Looking past the weather and at the personnel, I was the official counter on both of the record days, and I had either two or three people with me for the most part, with Charlie Barnard joining me both years, Tina Green and Frank Mantlik assisting for parts of the 2010 flight, and Bill Banks on hand for the day in 2011. We actually put in 8.25 hours on November 1 compared to the already stated 7.5 hours on October 28. Calculating the Red-tailed Hawk average per hour for the November 1 flight yields 30.18, and for the October 28 movement it comes in at 29.07, a minuscule difference. Obviously, the Turkey Vulture rates are much greater, with 23.03 per hour on November 1 and a mind-blowing 69.47 on October 28. Nearly every factor between the two days is identical except for this extremely abnormal Turkey Vulture count.
Snowtober
After examining every detail and nuance of the day of the historic flight and those leading up to it, I was left to scrutinize what came after, and having the very next day go down in New England weather history was a heck of a coincidence. Snowtober became a popular social media name for the devastating classic “winter” nor’easter that struck Connecticut and surrounding states on October 29 and 30, leaving catastrophic damage in its wake and well over a foot of snow in many areas. There are absolutely no comparisons to a storm of this magnitude occurring in October in any year, decade, or century, even apocryphal tales from colonial history. It was undoubtedly a multi-century event that left some birds in desperate straits, having to cope with an early snowfall of such a depth when many of those ill prepared for it had yet to vacate the northeast.
Frank Mantlik spent 1.25 hours at Boothe after the storm ended on the afternoon of October 30 with brutally strong northwest winds and saw 135 Turkey Vultures go by, as they were evidently still moving in marvelous numbers over the snow-covered landscape. I considered all of this more and more on Halloween, as it was a particularly “birdy” day on the shores of Long Island Sound, with birds like Savannah Sparrow and Eastern Bluebird flying in to Stratford Point in the middle of the day from the north. Stratford Point had no snow left whatsoever already after only a few inches falling that weekend and quickly melting on the comparably warm coastline. Had the Turkey Vultures been able to deduce that such a snowfall was on the way and planned their escape from the north the day before with such favorable conditions? Could they have possibly surmised a nor’easter would bury the ground and make finding carrion all the more difficult?
I readily admit such a suggestion may seem ludicrous, but after investigating all of what I have I am left with little other conclusion beyond tremendous coincidence and sheer luck. One might fall back to the fact we have scant data at Boothe Park in comparison to other sites, and although these sites have not had similar flights, we just be on the premiere Turkey Vulture flight path in the northeast United States. I wholeheartedly embrace such a title and welcome it with open arms, though I do not think we can make our acceptance speech quite yet. One remaining matter needs to be mentioned – what occurred at Lighthouse Point on October 28, 2011.
That other record
While we at Boothe Park were celebrating a wondrously successful day, the observers stationed at Lighthouse Point were shattering the previous record as well, as they tallied an astonishing 371 Turkey Vultures in 8.75 hours. As I mentioned earlier, their previous record, in over 40 years of nearly constant vigilant hawk watching, was only 135. This new total, nearly tripling the historic high count, is a strong piece of evidence in the argument that something was in the air on that day. If Lighthouse Point had totaled say, 150 or so Turkey Vultures, I think it could be seen as a new high count on a terrific day that could be expected as the population has grown to the north in recent years. But to so decimate the record that has been derived from decades of data suggests that this was truly a special event and gives us a hint that maybe, somehow, someway, these birds may have known what was in store for them had they not departed from the region as quickly as possible.
Perhaps results from next year will render all of this moot with an even more stupendous flight, but either way, a vulture’s ability to anticipate poor weather conditions it is something to consider. I cannot wait to see what the 2012 season has in store for us, and though it may be some time away, I invite you all to join us whenever possible as Connecticut Audubon Society increases monitoring efforts at Boothe Memorial Park. Once again, you can see more information, from directions to all of this data, on our HawkCount page here: http://www.hawkcount.org/siteinfo.php?rsite=703
Scott Kruitbosch
Conservation Technician
One of the many Turkey Vulture kettles from 10/28/11
On October 28, 2011, the hawk watch at Boothe Memorial Park in Stratford experienced an unprecedented event as those on hand tallied 521 migrant Turkey Vultures in only 7.5 hours of observation, obliterating any known flight record in New England and even some beyond. This astounding total was supplemented by 218 Red-tailed Hawks, a sum not to be relegated to an afterthought. The Red-tail count is believed to be the third highest in New England history, falling short of a Lighthouse Point total of 237 on November 7, 1999, and Boothe’s own total of 249 on November 1, 2010, the current record holder. Not coincidentally and as will be examined, that day held Boothe’s previous Turkey Vulture high count of 190, also one of the best ever in the northeast. In only the third year of opportunistic observation, Boothe has established itself as a regional force to be reckoned with when it comes to buteos and vultures, and a strong site for nearly every other Connecticut migrant raptor species.
Comparisons
It is safe to say that no one could have predicted the enormity of the Turkey Vulture explosion of October 28 as such a sum has traditionally been reserved for an elite group of watch sites with decades of experience. Many of these sites are far to our south, like Kiptopeke in Virginia, or buoyed with supreme geographical aids, as is the case in Cape May each fall or Braddock Bay in the spring. Cape May was one of my first thoughts at the conclusion of the epic day – specifically, had we come even close to touching one of their best flight days for Turkey Vultures? One has to bear in mind that they hold records that the vast majority of count sites can never dream of impinging upon. Seeing 1,023 Osprey or 278 Northern Harrier in one day is laughable for us here in Connecticut, but still not as impossibly insurmountable as daily totals of 7,000 Sharp-shinned Hawk or 1,231 Cooper’s Hawk are. For now, I can only dream that Boothe Park will complete an entire season with those sorts of numbers in the not too distant future.
Cape May’s top three Turkey Vulture flights are “only” 784, 607, and 602, still comfortably beyond the 521 we witnessed on October 28, but not at all embarrassing in comparison to Boothe’s new record. This immediately invigorated me, and I looked at many other sites in New England and the Mid-Atlantic, finding few if any that came even close to this spectacular fall flight. I already knew that Connecticut’s two major sites, Quaker Ridge in Greenwich and Lighthouse Point, in a combined total of over 80 years of observations, were nowhere close to our new record. Their top flights were 192 and 135, respectively. Moving out of state to a couple of other infamous sites, Franklin Mountain in New York topped off at 136 Turkey Vultures and Hawk Mountain Sanctuary in Pennsylvania peaked at 123, and several more locations were around these numbers. I should add one condition to these decades and decades of observations - the Turkey Vulture population is increasing to our north over time, and it must be understood that more migrants will be passing through, generally, every year. Regardless of that fact, Boothe’s total remains almost supreme amongst many similar and strong opponents.
The day’s weather
After that examination, the most obvious question remained: why did such an extremely high number of Turkey Vultures take to the skies to head south on this particular day? October 28 is in a range of time quite conducive to significant flights, though it is still relatively early in the season, with the last Boothe record occurring four days later the previous year, and the instant conclusion being that the date did not act like a late trigger to suddenly spur the birds south. One would presume beforehand that they would have kept migrating in a regular manner for another few weeks at the very least. I have already discussed the lack of totals approaching this one at other sites, thus for the moment making the small sample size of Boothe’s data somewhat less of a confounding variable, and this flight more of an anomaly. For the sake of argument, let us assume it was - that leaves us to wonder what exactly that trigger was and what in the world could have prompted this.
What remains is the weather, the conditions on and around this special day that helped to allow such an event to take place that Friday morning. The Tuesday before, October 25, had actually been a very productive day at Boothe Park with 276 raptors tallied, 76 of them Turkey Vultures, despite crystal clear blue skies. This flight in itself provides evidence that there were not birds being “backed up” by poor conditions for a week or more, and many had been able to move through Connecticut already. If there had been only a few raptors counted in the days before, or a continual southerly flow of some sort, a subsequent record flight might have been more understandable. That Tuesday movement came after a cold front passed through from a low centered well to the north in Canada and on northwest winds from high pressure moving through the Ohio Valley.
Realistic view of streaming Turkey Vultures going behind the clock tower earlier in the week before the historic flight
On that Wednesday and Thursday, October 26 and 27, the northeast region was plagued by a series of lows along a cold front that finally passed through Thursday night. As that front swiftly cleared our area and headed southeast, one of the biggest keys to the event came in the form of a superbly placed high moving in from the Great Lakes towards western New York and Pennsylvania just in time for the daytime hours on Friday. The pressure gradient was not very strong because of the rapid exodus of the front, and the high provided northwest winds of approximately 4-7 MPH for most of the day on Friday, a perfect strength to aid raptors moving south and gently push them to follow the coastline, but not thrust them all the way to the shore. This wind speed and direction has been shown to be optimal for Boothe Park on numerous occasions with it being a few miles off Long Island Sound.
2010 flight conditions
These conditions were, not coincidentally, nearly indistinguishable to the ones that provided the terrific flight at Boothe Park previously mentioned on November 1, 2010. The movement of the cold front, the placement of the high, wind speed and direction were all essentially the same, though there had been no cloud cover whatsoever that day. Turkey Vultures do sometimes fly by Boothe Park at high altitudes, though most go through at a moderate height compared to other species, and nearly all are detectable to the naked eye or binoculars even against the deep blue sky with their dark color and slow drifting style. Even when streaming through they often come in groups, thus the likelihood of missing a significant amount because of a lack of clouds, or finding more because of even partial cloud cover, is negligible.
Typical streaming Turkey Vultures at Boothe Park
Looking past the weather and at the personnel, I was the official counter on both of the record days, and I had either two or three people with me for the most part, with Charlie Barnard joining me both years, Tina Green and Frank Mantlik assisting for parts of the 2010 flight, and Bill Banks on hand for the day in 2011. We actually put in 8.25 hours on November 1 compared to the already stated 7.5 hours on October 28. Calculating the Red-tailed Hawk average per hour for the November 1 flight yields 30.18, and for the October 28 movement it comes in at 29.07, a minuscule difference. Obviously, the Turkey Vulture rates are much greater, with 23.03 per hour on November 1 and a mind-blowing 69.47 on October 28. Nearly every factor between the two days is identical except for this extremely abnormal Turkey Vulture count.
Snowtober
After examining every detail and nuance of the day of the historic flight and those leading up to it, I was left to scrutinize what came after, and having the very next day go down in New England weather history was a heck of a coincidence. Snowtober became a popular social media name for the devastating classic “winter” nor’easter that struck Connecticut and surrounding states on October 29 and 30, leaving catastrophic damage in its wake and well over a foot of snow in many areas. There are absolutely no comparisons to a storm of this magnitude occurring in October in any year, decade, or century, even apocryphal tales from colonial history. It was undoubtedly a multi-century event that left some birds in desperate straits, having to cope with an early snowfall of such a depth when many of those ill prepared for it had yet to vacate the northeast.
Frank Mantlik spent 1.25 hours at Boothe after the storm ended on the afternoon of October 30 with brutally strong northwest winds and saw 135 Turkey Vultures go by, as they were evidently still moving in marvelous numbers over the snow-covered landscape. I considered all of this more and more on Halloween, as it was a particularly “birdy” day on the shores of Long Island Sound, with birds like Savannah Sparrow and Eastern Bluebird flying in to Stratford Point in the middle of the day from the north. Stratford Point had no snow left whatsoever already after only a few inches falling that weekend and quickly melting on the comparably warm coastline. Had the Turkey Vultures been able to deduce that such a snowfall was on the way and planned their escape from the north the day before with such favorable conditions? Could they have possibly surmised a nor’easter would bury the ground and make finding carrion all the more difficult?
I readily admit such a suggestion may seem ludicrous, but after investigating all of what I have I am left with little other conclusion beyond tremendous coincidence and sheer luck. One might fall back to the fact we have scant data at Boothe Park in comparison to other sites, and although these sites have not had similar flights, we just be on the premiere Turkey Vulture flight path in the northeast United States. I wholeheartedly embrace such a title and welcome it with open arms, though I do not think we can make our acceptance speech quite yet. One remaining matter needs to be mentioned – what occurred at Lighthouse Point on October 28, 2011.
Will a sight like this from the historic day be common multiple times each year for us?
That other record
While we at Boothe Park were celebrating a wondrously successful day, the observers stationed at Lighthouse Point were shattering the previous record as well, as they tallied an astonishing 371 Turkey Vultures in 8.75 hours. As I mentioned earlier, their previous record, in over 40 years of nearly constant vigilant hawk watching, was only 135. This new total, nearly tripling the historic high count, is a strong piece of evidence in the argument that something was in the air on that day. If Lighthouse Point had totaled say, 150 or so Turkey Vultures, I think it could be seen as a new high count on a terrific day that could be expected as the population has grown to the north in recent years. But to so decimate the record that has been derived from decades of data suggests that this was truly a special event and gives us a hint that maybe, somehow, someway, these birds may have known what was in store for them had they not departed from the region as quickly as possible.
Perhaps results from next year will render all of this moot with an even more stupendous flight, but either way, a vulture’s ability to anticipate poor weather conditions it is something to consider. I cannot wait to see what the 2012 season has in store for us, and though it may be some time away, I invite you all to join us whenever possible as Connecticut Audubon Society increases monitoring efforts at Boothe Memorial Park. Once again, you can see more information, from directions to all of this data, on our HawkCount page here: http://www.hawkcount.org/siteinfo.php?rsite=703
Scott Kruitbosch
Conservation Technician
Tuesday, December 6, 2011
Winter of 2010-2011's toll on birds in Connecticut
The winter of 2010-2011 was one of the worst Connecticut has ever experienced, with some stations recording the greatest snow depth ever, the snowiest January ever, and one of the highest snowfall totals for an entire season. The Boxing Day Blizzard was only the beginning as the state took major hits several more times before all was said and done with a March 24 light snow event. Such a constant onslaught of snow can spell disaster for a number of bird species who succumb to the frigid conditions or perish when they cannot find sufficient food sources. Carolina Wrens, a resident species, are said to be a great indicator of how conditions impact birds as snow can take a toll on their population, preventing them from feeding on various invertebrates on the snow-covered earth. You may have seen some come to your feeders to eat primarily suet, or perhaps peanuts or peanut butter.
I wanted to see if this assertion was accurate or not, and how much their numbers changed from 2010 to 2011, so I decided to use eBird data to take a look at things. I chose to use data by year primarily because, apart from the blizzard in the last week of 2010, the snow for the season in question was focused all in 2011. I excluded December from the 2011 totals as checklists are still being submitted, and we must bear in mind some may still have yet to come in for other parts of the year as well. However, as of around 9 a.m. today, there have been 16,434 checklists submitted to eBird for Connecticut in 2011, and 14,410 for 2010, so sample size for each year does not appear to be an issue. I do acknowledge that we are dealing with data from hundreds of unknown observers of various skill levels across only two years, and it would be foolhardy to draw any certain conclusions.
Look at frequency first, the percentage of all checklists submitted reporting Carolina Wrens of any number in 2010 and 2011:
Whoa! There is a lot to look at here...
Looking back up to the frequency graph, we can also see a spike in the period after a consistent decline in December that went unnoticed when we first looked at it. Did the birds suddenly start showing up at backyard feeders in high numbers that week? Were more tallied during surveys because of sheer luck? Could some have been moving to the south a bit and through Connecticut? They are not said to be migratory. It may simply be a coincidence, but it makes one wonder what happened...and it makes my always suspicious and imaginative mind wonder if the wrens had a hint that we were about to be inundated with snow.
Finally, the total number of birds reported each period, a straight sum...
Perhaps if we start seeing a bunch of Carolina Wrens in our yards and at our feeders we will know some snow is on the way...hey, wait, I saw one looking for insects in the wheel of my car yesterday!
Scott Kruitbosch
Conservation Technician
I wanted to see if this assertion was accurate or not, and how much their numbers changed from 2010 to 2011, so I decided to use eBird data to take a look at things. I chose to use data by year primarily because, apart from the blizzard in the last week of 2010, the snow for the season in question was focused all in 2011. I excluded December from the 2011 totals as checklists are still being submitted, and we must bear in mind some may still have yet to come in for other parts of the year as well. However, as of around 9 a.m. today, there have been 16,434 checklists submitted to eBird for Connecticut in 2011, and 14,410 for 2010, so sample size for each year does not appear to be an issue. I do acknowledge that we are dealing with data from hundreds of unknown observers of various skill levels across only two years, and it would be foolhardy to draw any certain conclusions.
Look at frequency first, the percentage of all checklists submitted reporting Carolina Wrens of any number in 2010 and 2011:
Whoa! There is a lot to look at here...
- In 2010, there is a spike in the spring as breeding season begins, with males singing, territorial disputes, etc.
- There is also a drop in the middle of breeding season, as parents stay quiet and are busy feeding young, before a return to more constant levels
- See how fast the percentage falls from the last week of 2010, and the Boxing Day Blizzard, to the first week of January in 2011, though both years have falling numbers as winter approaches
- Then they plummet during the January bombardment of snow in 2011 compared to more constant numbers in 2010
- 2011 mimics 2010 in some regards with a slight spike in spring, and a decrease in breeding season
- The recovery is swift and by late summer and fall the 2010 numbers touch 2010 levels briefly
- While the current population is certainly less than 2010 at the same date, the breeding season definitely looks to have brought numbers of Carolina Wrens back up to some degree
- Once again, a good correlation between years with similar features
- Notice how the average number drops quickly in January in both years and spikes around June with pairs feeding young - while the species may be seen less, they are often seen together
- 2011's average is a bit less than 2010 overall, though not enormously
- However, the most obvious observation is what the heck is that spike?!
Looking back up to the frequency graph, we can also see a spike in the period after a consistent decline in December that went unnoticed when we first looked at it. Did the birds suddenly start showing up at backyard feeders in high numbers that week? Were more tallied during surveys because of sheer luck? Could some have been moving to the south a bit and through Connecticut? They are not said to be migratory. It may simply be a coincidence, but it makes one wonder what happened...and it makes my always suspicious and imaginative mind wonder if the wrens had a hint that we were about to be inundated with snow.
Finally, the total number of birds reported each period, a straight sum...
- Basically what we expected by now with the spring spike, winter drops, and the anomaly previously discussed
- There is a nice jump in both Octobers as well, with the highest level in 2011 outside of the rapid January decline
- Interestingly, the highest frequency in 2011 was also in October, though in another period
- One would figure this would occur after a successful breeding season, but why October instead of earlier in the fall or late summer?
Perhaps if we start seeing a bunch of Carolina Wrens in our yards and at our feeders we will know some snow is on the way...hey, wait, I saw one looking for insects in the wheel of my car yesterday!
Scott Kruitbosch
Conservation Technician
Monday, December 5, 2011
Western Kingbird continues
I surveyed our H. Smith Richardson Wildlife Preserve and Christmas Tree Farm again last week and enjoyed seeing the vagrant Western Kingbird continue to thrive in our field and grasslands habitat. It has been eating a few berries, though it is doing very well hawking insects in this unseasonably warm weather. It is fortunate to have such a pattern in place during a time where every night could easily be well below freezing. Here are a couple more photos and some HD video of it.
Later this week I believe we will finally begin to see some actual December-like weather, and I hope it chooses to move on back to the south sooner rather than later, as it may have already. I have not heard any reports of it in the last few days. Don't forget to buy a Christmas tree from us if you visit our preserve on Sasco Creek Road in Westport!
Scott Kruitbosch
Conservation Technician
Insect target acquired!
Later this week I believe we will finally begin to see some actual December-like weather, and I hope it chooses to move on back to the south sooner rather than later, as it may have already. I have not heard any reports of it in the last few days. Don't forget to buy a Christmas tree from us if you visit our preserve on Sasco Creek Road in Westport!
Scott Kruitbosch
Conservation Technician
Saturday, December 3, 2011
Connecticut Audubon Society to Develop Conservation & Management Plan for Aspetuck Land Trust’s Trout Brook Valley Preserve
By Twan Leenders
Conservation Biologist
Connecticut Audubon Society
Aspetuck Land Trust (ALT) announced plans in October this year to work with the Connecticut Audubon Society (CAS) to develop an adaptive management and conservation strategy for the Trout Brook Valley Preserve. The objective is to gather information to help ALT maintain Trout Brook Valley in a natural state while simultaneously supporting its public use goal, encouraging passive recreational use and enjoyment of the property. CAS is delighted to partner with ALT in this important project.
Over the course of a year, biologists and staff from the CAS Science and Conservation Office will carry out surveys to detect the presence of threatened, endangered or otherwise at-risk species in the Trout Brook Valley Preserve and to identify sensitive habitat areas contained within the preserve’s forested uplands.
Within the 1,009 acre preserve, spanning Weston and Easton, are vernal pools, shrub swamps, talus slopes, grasslands and other specialized habitats harboring plant and animal species. These species are uniquely dependent on these biological ‘islands’ within an otherwise largely forested area intersected by a 22-mile trail network. The trails were laid out gradually over the past 12 years, often without knowledge of these special microenvironments.
These specialized habitat pockets tend to be the first to disappear or become degraded when environmental pressure increases. The species that rely on them generally disappear simultaneously. Due to their very specific environmental requirements and because of the overall scarcity of the habitats they occupy, these specialized plants and animals tend to be rare and in need of protection.
We already know that the Trout Brook Valley preserve is home to some species included in Connecticut’s Endangered and Threatened Species Act. We believe that there are more to be found.
Across the state, Connecticut forests are gradually becoming more homogeneous with reduced species diversity and an increasing numbers of invasive species. At the same time rarer, more sensitive habitats and species slowly disappear. Highly adaptable plants and animals that can survive in a wide variety of habitats (the kinds of species that one tends to see in yards, parks and other areas associated with development – starlings, pigeons, squirrels, raccoons, coyotes, etc.) are very able to expand their range. Without careful land management, all our natural forests are at risk of becoming impoverished carbon copies of such disturbed habitats.
Importantly, this process takes place while the overall habitat may still look like a forest to the untrained observer. Effectively, more sensitive species are driven to extinction under our very noses! The quality and functionality of an area can be irreversibly damaged if no careful management and conservation strategy is put in place to maintain and protect healthy species and habitat diversity.
A carefully designed management and conservation plan based on relevant survey data will allow ALT to carry out its stewardship goal of maintaining the Trout Brook Valley Preserve in a natural state in a way that balances the need for protection of the area’s resources, plants and animals. Simultaneously, the study findings will help ALT fulfill its commitment to provide open space for passive recreational use and enjoyment of the property. Currently, regulated recreational uses of Trout Brook Valley include hiking, dog walking, hunting, fishing, and horseback riding. Hiking with off leash dogs has been suspended for a year while the CAS study is carried out.
The surveys carried out in the preserve will span an entire year, starting fall 2011 and concluding by fall 2012 to ensure complete coverage of all seasons (not all plants and animals are visible year-round). This prolonged survey period will also allow Connecticut Audubon Society staff to evaluate a wide variety of factors that could potentially affect the preserve’s future health. These range from the spread of invasive plants, plant diseases and pests, to the location of the existing trails and the management practices used to maintain sections of the property.
Throughout the year there will be opportunities for interested members of the public to directly help us and participate in the surveys. Please stay tuned for more information!
=====================
You may have noticed a taste of the results of our survey work already here in the blog. We are very excited about the data collected so far, and we will keep you up to date from time to time with any particularly noteworthy, intriguing, or just plain cool discoveries during our progress.
Scott Kruitbosch
Conservation Technician
Conservation Biologist
Connecticut Audubon Society
Aspetuck Land Trust (ALT) announced plans in October this year to work with the Connecticut Audubon Society (CAS) to develop an adaptive management and conservation strategy for the Trout Brook Valley Preserve. The objective is to gather information to help ALT maintain Trout Brook Valley in a natural state while simultaneously supporting its public use goal, encouraging passive recreational use and enjoyment of the property. CAS is delighted to partner with ALT in this important project.
Over the course of a year, biologists and staff from the CAS Science and Conservation Office will carry out surveys to detect the presence of threatened, endangered or otherwise at-risk species in the Trout Brook Valley Preserve and to identify sensitive habitat areas contained within the preserve’s forested uplands.
Within the 1,009 acre preserve, spanning Weston and Easton, are vernal pools, shrub swamps, talus slopes, grasslands and other specialized habitats harboring plant and animal species. These species are uniquely dependent on these biological ‘islands’ within an otherwise largely forested area intersected by a 22-mile trail network. The trails were laid out gradually over the past 12 years, often without knowledge of these special microenvironments.
Risks of Disappearing Species
These specialized habitat pockets tend to be the first to disappear or become degraded when environmental pressure increases. The species that rely on them generally disappear simultaneously. Due to their very specific environmental requirements and because of the overall scarcity of the habitats they occupy, these specialized plants and animals tend to be rare and in need of protection.
We already know that the Trout Brook Valley preserve is home to some species included in Connecticut’s Endangered and Threatened Species Act. We believe that there are more to be found.
Across the state, Connecticut forests are gradually becoming more homogeneous with reduced species diversity and an increasing numbers of invasive species. At the same time rarer, more sensitive habitats and species slowly disappear. Highly adaptable plants and animals that can survive in a wide variety of habitats (the kinds of species that one tends to see in yards, parks and other areas associated with development – starlings, pigeons, squirrels, raccoons, coyotes, etc.) are very able to expand their range. Without careful land management, all our natural forests are at risk of becoming impoverished carbon copies of such disturbed habitats.
Importantly, this process takes place while the overall habitat may still look like a forest to the untrained observer. Effectively, more sensitive species are driven to extinction under our very noses! The quality and functionality of an area can be irreversibly damaged if no careful management and conservation strategy is put in place to maintain and protect healthy species and habitat diversity.
Meeting ALT’s Stewardship Goals
A carefully designed management and conservation plan based on relevant survey data will allow ALT to carry out its stewardship goal of maintaining the Trout Brook Valley Preserve in a natural state in a way that balances the need for protection of the area’s resources, plants and animals. Simultaneously, the study findings will help ALT fulfill its commitment to provide open space for passive recreational use and enjoyment of the property. Currently, regulated recreational uses of Trout Brook Valley include hiking, dog walking, hunting, fishing, and horseback riding. Hiking with off leash dogs has been suspended for a year while the CAS study is carried out.
The surveys carried out in the preserve will span an entire year, starting fall 2011 and concluding by fall 2012 to ensure complete coverage of all seasons (not all plants and animals are visible year-round). This prolonged survey period will also allow Connecticut Audubon Society staff to evaluate a wide variety of factors that could potentially affect the preserve’s future health. These range from the spread of invasive plants, plant diseases and pests, to the location of the existing trails and the management practices used to maintain sections of the property.
Throughout the year there will be opportunities for interested members of the public to directly help us and participate in the surveys. Please stay tuned for more information!
=====================
You may have noticed a taste of the results of our survey work already here in the blog. We are very excited about the data collected so far, and we will keep you up to date from time to time with any particularly noteworthy, intriguing, or just plain cool discoveries during our progress.
Scott Kruitbosch
Conservation Technician
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