In an exclusive excerpt in our October 2013 issue, the authors of the new Peterson reference guide to seawatching revealed the tricks of the trade that experts use to identify distant, fast-flying waterbirds. Here, they explain why seawatches matter:
There are dozens of regularly operated hawk watches throughout North America, with a concentration in the northeastern United States. Several of these watches have annual data going back to the 1970s or earlier.
These watches form a powerful network whose data are analyzed together, with the aim of tracking population trends in North American raptors. They have succeeded admirably in this goal, documenting the recovery of the Bald Eagle and Peregrine Falcon, the rise of Cooper’s Hawk, and the decline of American Kestrel and Sharp-shinned Hawk. The data from any one watch could easily be dismissed, but data from dozens of watches over a broad area that reflect similar trends are hard to ignore.
Unfortunately, no such network exists for waterbirds, despite the conspicuous diurnal migrations most species undertake and an abundance of sites with significant concentrations of migrants. The fall seawatch in Avalon, New Jersey, administered by Cape May Bird Observatory and New Jersey Audubon Society, and the waterbird count at Whitefish Point, Michigan, administered by Whitefish Point Bird Observatory, are the only official long-term watches collecting data on the trends in waterbird migration. Certainly there are other means of monitoring waterbirds, and the population trends in game species such as geese and ducks are carefully tracked by government agencies. Even among ducks, though, a cohesive strategy for monitoring the sea ducks that nest in the far north, such as scoters and eiders, does not exist.
Admittedly, some of the least-known species in the direst need of population monitoring, such as Black-capped Petrel and Ivory Gull, are not well suited to monitoring by seawatching. Even so, what additional knowledge might be gained about waterbird populations, trends, and movements if there were a network of regularly operated waterbird counts similar to the network of hawk watches?
The steady decline in the numbers of Common Loons at the Avalon Seawatch, and the timing of their movements, are not paralleled by the data gathered at less formal watches on the eastern Great Lakes. Are the birds recorded in the Mid-Atlantic coming from a different breeding population than those passing through the Great Lakes? What is the meaning of the occasional huge incursions of Razorbills to the Carolinas south of the normal range of this species? So far there has been little effort to systematically gather and compare numbers of Razorbills seen in the Southeast over time and correlate them to larger population trends in this species or with the status of the fish on which Razorbills depend. Such examples only touch on what could be discovered if there were more birders seawatching and recording numbers in a systematic manner. – Ken Behrens and Cameron Cox
From Peterson Reference Guide to Seawatching: Eastern Waterbirds in Flight by Ken Behrens and Cameron Cox published by Houghton Mifflin Harcourt in September 2013. Copyright © 2013 by Ken Behrens and Cameron Cox. Reprinted by permission.