Falkland Islands, 9 July 2010
By Keith Bildstein, Ph.D.
Hawk Mountain Sarkis Acopian Director of Conservation Science
Raptor biologists are known for going to extremes to get to their birds. My three trips earlier today to the waste disposal site at Eliza Cove in the Falkland Islands—the locals call it the Stanley Dump–are a case in point.
The dump is about three miles from downtown Stanley, the tiny Falkland Islands capital that boasts fewer than 2,500 inhabitants, a single petrol station, and not a single traffic light, and is about 10,000 miles south of Hawk Mountain in the South Atlantic. More than 400 kilometers off the Patagonian coast of Argentina, the Falklands are in the middle of nowhere, but what a beautiful nowhere it is. Aside from its largely uninhabited landscapes, the islands host a singularly unusual resident population of high-latitude Turkey Vultures (the Falklands are 50 degrees south of the Equator), and I have been studying this odd population of scavengers since 2006. Hence my visits to the dump.
My interests are twofold.
First and foremost is a genuine conservation concern. The Falkland Islands government currently issues shooting permits for more than 100 “nuisance” vultures each year (the birds are thought to interact negatively with sheep), and Hawk Mountain’s work in the Falklands focuses on better understanding the impact that this “take” has on the population and how we should best go about eliminating, or at least reducing, it.
Second, the Falkland Islands offer a textbook case of “an-exception-that-proves-the-rule,” in avian biology… to wit, Turkey Vultures being migratory at latitudes greater than 45 degrees north and south of the equator. Simply put, the biological question boils down to this: “how does a population of 6,000 to 8,000 vultures manage to prosper on a wind-driven, Connecticut-sized archipelago surrounded by near sub-Antarctic waters.”
Which brings me back to the Stanley Dump.
Each Austral winter (i.e., late May through late August) more than 100 Turkey Vultures breeding in the countrysides and coastlines near Stanley converge on the island capital, where they use the trash dump as a reliable feeding station and a small grove of Macrocarpa evergreen trees in the center of town as a cozy roosting site. The trash heap/vulture restaurant makes for a perfect trapping site, and that is why I have been visiting it for four of the past five years. In the past we have used large box traps to catch the birds, but this week we are experimenting with 80-pound test monofilament noose lines.
The experiment is going well. We are catching vultures.
Each bird we trap is first weighed and measured and then fitted with a numbered yellow, herculite wing tag. Falkland Islands Conservation, the local Birdlife International partner on the islands, acts as the “call center” for reports of tag re-sightings, and the accumulating information coming in from the locals and tourists visiting the islands is helping us study the movement ecology of the birds.
Earlier this morning I counted 89 vultures at the dump, one of my highest tallies ever. Unfortunately none was sporting one of the 50 bright yellow wing tags we have tagged them with since 2007. My mid-day count shrank to 19, but one of the birds, tag number 02, had been marked at the dump in the winter of 2008.
My trapping colleagues Marc, Sam and Roo, and I baited the area with cattle rib-cages at 1 PM and came back again at 3 PM to set our traps. We caught our first bird in less than five minutes, and a second 20 minutes after that. Both were tagged and released within minutes. Our only problem today was by-catch. Hundreds of Dolphin Gulls and Kelp Gulls also feed on refuse at the dump, and we caught several of each in our monofilament snares. Carefully removing them without being bitten is something of an art, and we are still learning how to do it properly. That said, today has been a good day both for re-sightings and trapping.
Tomorrow I leave on an afternoon flight to Chile, Brazil, and then on to Newark, New Jersey. The plan is trap for several hours tomorrow morning as well. The work is slow and steady, but exceptionally exciting nevertheless. A master’s degree thesis currently completed by Brandon Breen, a University of Minnesota graduate student supported by Hawk Mountain, will summarize the first three years of our work. An additional three years of study, which will include capturing, wing tagging, and following Caranchos (Southern Caracaras) and Johnny Rooks (Striated Caracaras)–two other prominent scavengers on the islands–is in the works.
I plan return the Falklands next July for more visits to the Stanley Dump. But before I do, I will make certain I wash my boots and field clothes. The dump stinks.
(Photos courtesy of Ruairidh (Roo) Campbell.)
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