Last week I participated in one of the oldest and most important citizen science projects in all of ornithology, the venerable Breeding Bird Survey. At this time of year, volunteers all over North America are participating in this survey, covering over 4000 individual routes.
Overseen by the US Geological Survey, the BBS, as it is known, was established back in 1966 by well-known ornithologist Chandler Robbins out of concern for the effects of DDT on bird populations. Since then, this now indispensable long-term dataset has been used in hundreds of studies to show trends in bird populations across the continent.
The methodology for the Breeding Bird Survey sort of turns bird surveys into an Olympic sport. It requires applying a lifetime of finely-honed bird identification skills, mostly by ear, at 50 painfully brief stops along a breathless 25 mile route. Since you have to complete the route in 4-5 hours, there’s no time to spare. Slack-jawed dawdling, lingering, and puzzling over mystery birds for more than a few seconds is not allowed. Given that I am an accomplished slack-jawed dawdler when it comes to birding, it take a focused effort on my part to get this thing done in time. Luckily it is unlike most Olympic events in that you can drive the route in a car, which in turn facilitates the consumption of donuts and coffee during this otherwise grueling event.
I was lucky to have the help of local birder and bird bander Sue Finnegan on survey day. We met at 4AM sharp, giving us just enough time to get to the starting point in South Truro by 4:37, exactly one half hour before sunrise. There’s an alarming amount of traffic on route 6 already, but by the second stop we are on heavily forested back roads in the National Seashore where bird song is all we can hear. A clipboard contains everything we need – detailed descriptions of all 50 stops, maps, instructions, and data sheets.
At stop two, the gorgeous flute-like song of a Hermit Thrush, the only one we will hear all morning, barely reaches our ears from well off into the forest. A male Scarlet Tanager sings from fairly close with a slight buzzy quality that lets us know he’s not the similar sounding American robin. He will also be our only tanager in 5 hours of surveys.
The oak woods of Truro have been hit very hard by gypsy moths for a third year in a row. Beautiful, relatively gigantic valley bottom oaks are skeletonized, giving a February look to a June day. The birds are still breeding in these eerie woods – we hear both Yellow-billed and Black-billed Cuckoos, several Eastern Wood-Pewees, Brown Creepers, and uncommon breeding songbirds for the Outer Cape like Black-and-White Warbler and Blue-gray Gnatcatcher. Of these, only the cuckoos can actually eat the gypsy moth caterpillars. We only encounter a few, puzzling given the surfeit of food available to them. Other species are making do with other trees less affected by the plague of caterpillars, like Black Locust. Or maybe all the extra sunlight reaching the forest floor has produced a flush of insects in the undergrowth.
Over five hours and 50 surveys later, we stumble across the finish line in Nickerson State Park in Brewster, adding our first Red-eyed Vireos and a calling Wood Duck to the morning’s list. All of the data will go to the USGS folks down Maryland, who will add it to this impressive 50 year data set on North American bird populations. The data is available for download and perusal on the BBS website, along with trend analysis for 420 species.
As for me, I’m currently in training for next year’s survey, when I will look to shave even more minutes off our total time. I’m mainly focusing on a technique for eating my donuts even faster.