Netting For Gold


By Dylan O’Leary, AmeriCorps Field Assistant for The Nature Conservancy on June 12, 2017

At 6:00 AM, the spring sunrise is in full bloom over the Helen W. Buckner Memorial Preserve, a Nature Conservancy treasure.  The morning dew, shining like glitter, has our boots soaked after the first few steps. The sweet scent of flowering honeysuckle mixed with the lemon eucalyptus oils of bug spray, brings back the fondest memories of past springs. By now, the dozens of species of birds we hear around us have been singing for over an hour, incessantly reminding the world of their respective territories. We can just make out their silhouettes against the intensely backlit sky as they flit to and fro among the tree tops and shrubs. From the cacophony of tweets, buzzes and caws, one song rises above the rest: the “bee-buzz” of the blue-winged warbler.

Together with fellow AmeriCorps member Josh Duncan, I am accompanying Conservancy Critical Lands Manager Murray McHugh, and two Audubon VT biologists, Mark LaBarr and Margaret Fowle, on a mission to learn more about the golden-winged warbler (GWWA) and blue-winged warbler (BWWA) populations in Vermont. GWWA have sustained sharp population declines over the last 50 years and are listed as Near Threatened by the International Union for Conservation of Nature (IUCN). Habitat loss and competition with the closely related BWWA have reduced their numbers and shifted their range northwest making VT part of the very eastern edge of their existence. Buckner preserve sustains the largest population in the northeast of these dynamic little birds and Murray McHugh has been working hard to keep it this way.

We are barely a quarter of a mile into Tim’s trail when Mark and Margaret find a perfect spot to assemble the 25 ft. long by 15 ft. tall net with thread so fine it can barely be seen from several feet away. Nestled in a narrow slot among head-high stands of gray dogwood, honeysuckle and prickly ash with a nearby hardwood forest and plenty of open space in between, we are in prime early successional habitat for GWWA and BWWA. As Margaret sets up her iPhone to broadcast GWWA territorial calls, Mark adds the pièce de la résistance: a perfect, handcrafted wooden replica of a GWWA female propped on a stick. The trap is set and we watch from a stone’s throw away.

Our task is to capture as many warblers as possible to maximize our chances of recapturing individuals outfitted with geolocator backpacks. These M&M sized devices weigh less than a tenth of a gram and use a light detection system to record light at regular intervals throughout the day. Since day length varies with latitude and solar noon varies with longitude, this light data can be decoded into coordinates, granting biologists a detailed look at the migration habits of these birds. 13 backpacks were deployed in 2016 and evenly distributed between GWWA and BWWA individuals.

At first, there is silence as the warblers adjust to the new strange call. Then, with renewed conviction, the warblers begin calling back and fly towards the intruder. They dart from bush to bush furiously, pausing only momentarily between calls to frantically scan their surroundings. The five of us are holding our breath, watching intently through binoculars, muttering in response to each and every move. They’re flying mere inches away, almost flirting with the net until finally, one is caught!

Mark responds immediately, and rushes over to disentangle our new startled friend. Each captured bird is weighed, aged, visually inspected for health and given a tiny metal band with a unique ID number around its ankle. The first three birds are actually Brewster’s hybrids, the dominant genotype of a GWWA and BWWA cross. At our next trapping spot, we finally hit the jackpot: a BWWA with a backpack! Mark and Margaret work carefully to cut the tiny threads of the harness and free the feisty warbler of its burden. With a years’ worth of location data, ornithologists can begin to pin-point vital feeding grounds and resting spots these warblers use on their extraordinary journey to South America.

“Thank you for your service little guy” Murray said as we prepare to release him. Thank you indeed; each little backpack-carrying bird could be the key to conserving not only the golden-wing warblers, but also every other species that relies on similar habitat. With a breeding season that runs through much of June, I’m looking forward to spending many a sunrise collecting the rest of the backpacks and contributing to the hopeful rebound of this beautiful creature.

Categories: birds, science, AmeriCorps, Buckner Preserve





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