Wednesday, October 20, 2010

Name this migrant raptor

On Monday, I spent some time at the Boothe Park Hawk Watch. I got there at about 8AM despite the fact that the site performs poorly for raptors in the early morning hours. The few that move early are still low and therefore out of our sight, not able to climb in altitude because thermals (rising warm air) have not formed yet. I wanted to count migrant passerines species. For example, I had noted many Yellow-rumps coming in to the site lately from the east, flying through or stopping to feed. I had over 150 one morning last week.

While performing that count I was also watching the sky for any raptors, of course. A handful may go through even if there are not large numbers until later in the morning. The first raptor of the day looked quite odd to me. It was still overcast to the east, with blue sky overhead and back to the west. The bird came in from the east and was backlit by the small amount of sun there was. See if you can figure out what it is.

Any ideas? Do you know the family? That is a very tough view. As it moved a bit closer it continued to look abnormal, but I was relatively certain of what it was by the time I snapped the below photo. I was in disbelief, though.

From that point, I watched the bird until it was over my head, a good time to snap more photos. It was in the blue by now and moving between the sun and me. The photo below should be enough for some experienced birders.

Below is another overhead shot as it moved further away. It flew off to the southwest, continuing on a perfectly typical migrant raptor route for our site even if it was far from a typical raptor.

Do you know what it is? If you want to guess for a bit longer stop reading here for now..... is a Short-eared Owl! The Cornell All About Birds account has an excellent low flight photo for comparison to my overhead shots.

After instinctively thinking it was a Northern Harrier for a few seconds, I noticed it was coming in with too much of a floppy, floating, flight. It also had a thick body with a large, flat, head. From there it was simply a matter of figuring out what owl species was flying towards me. The large size dismissed small species like Northern Saw-whet Owl or Eastern Screech-Owl. The wing characteristics helped a bit. They were too narrow and long in proportion to the body for a Great Horned Owl or Barred Owl, and as is obvious even in the photos the plumage was much too light for either species. By the time it was overhead the only other realistic option in my mind was a Long-eared Owl. However, the size, placement, and size of the bars on the underside of the wings and streaking on the breast, as opposed to dark barring, make it a Short-eared Owl.

Another part of what lead me to thinking it was a Short-eared Owl rather quickly was the fact they are less nocturnal than most owls, often hunting in the early morning or late evening. Long-eared Owls are strictly nocturnal, while Great Horned and Barred are only rarely seen in the daylight hours. Seemingly little is known about Short-eared Owl migration, but this was clearly a migrant individual. It followed the typical Boothe Park raptor migrant pathway without any sort of deviation or pause at an altitude that, while low for most raptors, is much higher than typically seen in the species. I was happy to get the photos I did. I do not think I would have believed myself if I did not.

Photos © Scott Kruitbosch

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