Thursday, March 28, 2013

Rusty Blackbird work continues

I wanted to point your attention to this eBird piece on the Rusty Blackbird. It summarizes some of the incredibly important work being done by members of the International Rusty Blackbird Working Group (IRBWG) in order to save a species that is falling in numbers as fast as any in North America.
Have you heard the creaky rusty-hinge song of the Rusty Blackbird lately? Historical accounts paint pictures of an abundant species, easily observed in boreal forest wetlands during the breeding season and wooded wetlands throughout the winter. These days, birders are lucky to catch a glimpse of these often-overlooked birds; Rusty Blackbirds have experienced one of the steepest population declines of any once-common North American bird.  Estimates from the last decade suggest that Rusty Blackbirds have experienced an 85-99% population drop over the past 40 years. For the past decade, scientists have been seeking to unlock the secrets of the enigmatic Rusty Blackbird population crash.

IRBWG members like me have spent time examining migration and movement of the species, breeding behaviors and nesting data, habitat usage in all seasons, and outside pressures from pollution to predators to other competing species. Connecticut is only a migratory and limited wintering region for the species but there is still plenty to document. We often still do not know the basics such as what other species they associate with, what they are feeding on, which habitats and locations are the most productive in the winter, significant stopover sites, the sex and age of birds at these various times and places, and so much more. I have recorded all that is possible about the species whenever I have encountered it and continue to try to bring attention to their decline. The Rusty Blackbird Winter Blitz was run in a two-week period in 2009-2011, and we will once again be asking for the public's help in March and April 2014 during the Rusty Blackbird Spring Migration Blitz.

One part of the eBird piece that I feel is important to discuss here involves a great insight made by Sam Droege of USGS within the discussion list of the IRBWG. Above you can see I quoted that it is believed, "Rusty Blackbirds have experienced an 85-99% population drop over the past 40 years", a staggering number in itself. However, this is really underestimating their plight and discounting their nearly unfathomable downfall. The key part is "over the past 40 years" as it excludes everything prior to about 1970 and the era of the Breeding Bird Survey. In the late 19th century the species was far more common than the mid to late 20th century. I would speculate that we are probably looking at drop near 99% if one was to go back 100 or 125 years in the history of the species. Sam is right in that we often incorrectly have a tendency to discount any data or information much older than a generation. While it may be much more abstract in nature all of those scientists writing down their observations a century ago should not be forgotten, and we should remember that we are dealing with a bird that is in an extremely treacherous and perhaps fatally silent spiral towards extinction.

Scott Kruitbosch
Conservation Technician

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