Wild Side: Our Breeding Bird Survey

The northern parula warbler may be on an upswing.

A male northern parula. Breeding Bird Surveys help monitor the populations of scarce breeders such as the northern parula. —Ken Magnuson

Starting in the year 2000, one of my mornings every June has been devoted to helping a massive “citizen science” project called the Breeding Bird Survey (BBS). Run by the U.S. Geological Survey since 1966, the BBS as a whole comprises more than 4,000 routes, covered for the most part by amateur observers donating their time. Routes are run using a standardized procedure, and in aggregate, BBS results are a valuable tool for monitoring breeding bird populations and distribution.

With the bureaucratic sobriquet “47-102 Gay Head,” the Vineyard’s sole BBS route starts at 4:37 am at Lobsterville and then winds, like all other BBS routes, through 25 miles and across 50 equally spaced stops. At each stop, the observer watches and listens for exactly three minutes, recording all birds heard or seen within a specified radius. It’s a tiring exercise, but a fun one, and my route always provides a welcome look at how the season is shaping up for Island bird life.

I run my route on a Sunday morning if possible, since automobile traffic noise on other days makes the final 15 or 20 stops on the route totally unworkable. This year, pouncing on an idyllic forecast of clear skies and little wind, I ran the route on June 4 — earlier in the season than I’d like, but within the permissible range of dates for this route.

On this, my 18th repetition of the exercise, things ran about as smoothly as they could. While I kept an eye on the odometer to locate stops, my real cues came from memory: A certain guardrail, road sign, or driveway marks each stop, and I was out of the car and back on my way in barely more time that the prescribed three-minute count period.

(Reliance on landmarks is especially helpful with this route. It was set up many years ago by the late, great Vern Laux, who had no objection at all to massaging the half-mile spacing to position stops at especially promising locations!)

With a few pauses to recaffeinate on tepid tea from a Thermos or to spend a few extra moments with an enjoyable bird, I finished in just under four hours. A BBS is data collection, which is not the same thing as birding. The point is reliability and consistency, not finding rarities. Still, stumbling over an unusual bird, even a bird unusual just by the standards of the BBS route, is part of the fun.

Hands down, the most unusual find among this year’s 61 species was an alder flycatcher, singing from a wetland in Aquinnah. Rarely detected on the Vineyard by conventional birding, this species has actually figured three times now on this BBS route. Not known to breed here, alder flycatcher nevertheless shows a pattern of arriving and acting territorial, sometimes for several days, in early June. While a nesting pair on the Vineyard would be a distinct outlier on this bird’s breeding range, I regard it as a real possibility.

A few other species fall into the class of common birds that the BBS protocol is simply poor at detecting. Whip-poor-wills, for example, are strongly nocturnal, and rarely sing during daylight. This year, I caught one winding down its song in the half-light of my first stop at Lobsterville. Likewise, the activity pattern of chimney swift, though it’s common on the Vineyard, tends not to overlap with BBS hours. A single chimney swift in West Tisbury was the first on this route in many years.

Then there are the common birds! And there is nothing like a BBS route to make one realize just how numerous some of our breeding birds are. I tallied 75 gray catbirds, an average of 1.5 at each stop, which surely extrapolates to an Island breeding population well up into the thousands. And I heard or saw 51 eastern towhees, including seven individuals at one stop in Aquinnah.

Perhaps most gratifying was a tally of five northern parula warblers, across four up-Island stops. While I record this species most years, five is the most I’ve ever picked up, and it was a particular pleasure to hear two males “countersinging” — engaging in a sort of sonic territorial competition — along the North Road.

Listed as “threatened” in Massachusetts, parulas are largely restricted as breeders in the Bay State to wet woodlands on the Cape and Islands. Evidence on their current status is inconsistent. The state’s Natural Heritage Program, relying on records submitted to the state, considers the species to be precarious and declining. A recent Breeding Bird Atlas compiled by Massachusetts Audubon is a bit more sanguine, showing a modest increase in the Cape and Islands and a notable increase in “possible” breeders (most of which were probably late migrants, but still …) in western portions of the state.

My own take, based in part on BBS Route 47-102, is that this elegant treetop denizen may be gradually increasing in numbers here. If so, it’s another way in which the Vineyard plays a crucial role in harboring the commonwealth’s biodiversity.