Epic Avian Migrations Yield Astonishing Insights
Out of sight, out of mind? That mindset may characterize the thoughts of many Upper Valley residents about migratory birds during the extended period when they are far from our area. We welcome them back from far-flung winter homes in April or May, but where exactly have they been? And, how did they get there?
First, bear in mind that most of our familiar and beloved avian summer residents — from the Wood Thrushes in our forests, to the Bobolinks in our meadows, to the Killdeer in our driveways and barnyards — spend a far greater period of time away from their Upper Valley haunts than they do here. Most migratory birds that nest locally grace us for no more than four months. The remainder of their year is spent in transit or in winter quarters that may be more than 5,000 miles to our south. They encounter countless perils en route, and, too often, their winter habitats are threatened by the myriad effects of human-related change. How well a Baltimore Oriole, Scarlet Tanager, Broad-winged Hawk, or Ruby-throated Hummingbird fares during migration and in winter plays a huge role in its overall conservation.
Recent research by VCE has discovered that two long-distance migrants undertake southward fall flights that are among most extraordinary migratory feats on the planet. For both, technology revealed the astounding details. We’ll start with the Blackpoll Warbler, a diminutive 12-gram bird that nests on New England mountaintops (including Smarts and Ascutney) and across the vast taiga of boreal Canada. The species had been long rumored, but never proven, to undergo an epic non-stop, overwater autumn flight from the northeastern U.S. to its wintering grounds in northern South America. In 2013, VCE attached light-sensing geolocators to the backs of 19 breeding male Blackpoll Warblers on Vermont’s Mt. Mansfield, while our colleagues in Nova Scotia affixed the same devices to 19 males there. The rest is history. We recovered 5 of these tiny backpacks in 2014 (Blackpolls are very “faithful” to their breeding sites). Downloading the geolocator data confirmed that every bird had struck out in early October from the Northeast coast, winged over the open Atlantic to the Caribbean, then continued on to Colombia or Venezuela. Non-stop flight times ranged from 49-73 hours over distances that averaged 1,580 miles! One Blackpoll’s overwater flight covered 1,709 miles in a mere 64 hours.
The Upland Sandpiper is no migratory slouch either. This grassland specialist hasn’t nested in the Upper Valley for decades, and, like other grassland birds, is declining across most of its North American range. It spends winters in the pampas of Argentina, Bolivia and Uruguay. VCE is spearheading a study of “Uppies” on Dept. of Defense lands, and this past summer we outfitted 15 birds with satellite tags in MA and KS. Four of these are carrying solar-powered tags that send us their daily location via email (that’s right, email!). Two tagged birds flew non-stop from MA over the Atlantic Ocean and Caribbean Sea to Venezuela, while a female tagged in KS in April has visited no fewer than ten countries and traveled more than 6,000 miles so far on her way south to Uruguay! Results are preliminary, but dazzling, and critically informative to help us understand the year-round ecology and conservation needs of this vulnerable species.
So, as you gaze out at the snow swirling over Upper Valley fields and cloaking our mountains in the months ahead, remember the epic migrations of Blackpoll Warblers and Upland Sandpipers. They’ll be back a few months from now; their endurance and grit should inspire us all