Birds of a feather
Researcher finds special bond — and discoveries — among giant petrels
Posted February 26, 2010
Donna Patterson-Fraser moves swiftly across the rocks on Humble Island, deftly leaping from stone to stone to avoid damaging the fragile moss that forms a threadbare carpet across the island and between the giant petrel nests along her route.
She and fellow field team member Kirstie Yeager also must weave around the small colonies of Adélie penguins — packed into irregular circles where the ground is stained light pink with guano — and the muddy wallows created by elephant seals. To call their combined smell “pungent” falls far short of the reality. It’s as if everything at a seafood market has turned strongly rancid.
But Patterson-Fraser and Yeager quickly pass the animals, hardly wrinkling their noses at the birds or the ill-tempered seals, the latter throwing their weight around to steal penguin territory.
Check out the video
Visit YouTube for a video of Donna Patterson-Fraser and Kirstie Yeager working with giant petrels on Humble Island and elsewhere near Palmer Station.
One monstrously big seal barks and jiggles dangerously close to a colony. Weighing up to three tons, a bull can easily flatten a colony’s fragile chicks, even though some now stand nearly as tall as their parents do. Patterson-Fraser pauses long enough to curse the bully, as one feisty Adélie brays and jabs its beak at the trespasser, actually forcing the elephant seal to retreat.
“The Adélies have a tough enough time already. Now they have to deal with that,” says Patterson-Fraser, referring to the growing population of elephant seals on Humble. A changing climate along the northern tip of the Antarctic Peninsula has sent the local Adélie population into a steep decline over the last several decades as sea ice, a key habitat, has significantly retreated in duration.
But that’s not the story Patterson-Fraser and Yeager are interested in today. They’re on Humble Island to weigh and measure the snowy white chicks of southern giant petrels.
It’s a job that members of Bill Fraser’s field teams have been doing for more than 15 years now. Fraser is the principal investigator for the seabird component of the Palmer Long Term Ecological Research (PAL LTER) program , a mostly ship-based ecosystem study across a 700-kilometer swath on the western side of the Antarctic Peninsula.
The “birders” spend most of their energy tracking the bird populations close to Palmer Station on some 20 different islands, though some work is done farther south off the U.S. Antarctic Program’s research vessel, the ARSV Laurence M. Gould . The ship supports the LTER cruise every January, while the birders island-hop for their annual seabird census from October to March on inflatable rubber Zodiac boats.
In the early 1990s, Fraser’s work had focused on the penguins and a few other seabirds, like the intelligent and long-lived brown and south polar skuas. Patterson-Fraser wondered why he didn’t also work with the giant petrels.
“There’s got to be a story here,” she recalls telling Fraser, whom she started working for during the 1991-92 summer field season.
But the birds had a reputation as being difficult to handle. They “gaked” — a vile, oily stream of stomach contents — to defend against enemies. They’ll gak on you, Fraser warned her, but gave her the go-ahead to try.
The warning didn’t deter Patterson-Fraser, a short but energetic woman with a pale complexion burnished bright red by wind. She picked out a loop of nests that she watched for an entire season — basically becoming acquainted with the birds.
“You’ve got to take the time to watch and learn the signals,” she says. “They’re easier than people. I’m not a people person. I’m animal person. … You don’t have to second-guess what they’re thinking, because they’re straight up with you. And you never worry about them talking smack after you left; they’ll just talk smack right to your face.”
After making protracted introductions that first season, Patterson-Fraser then proposed the team start tracking the growth of the chicks as a way to assess the parents’ ability to care and raise them to maturity. Fraser repeated his warning: You’ll get gaked on.
Every day she would visit the nests, gaining the birds’ trust. Every day, Fraser asked if she had been slimed by giant petrel gak. It never happened.
“He was almost disappointed by that,” she says.
Within two years, she had gained the trust of the giant petrels, which allow her to handle the chicks so she can weigh them and measure their culmen, or beak. A scavenger and predator, giant petrels are roughly the size of a bald eagle, with a hooked beak that can easily rip into whale flesh. They roost on rocky high points across the islands, making their nests out of small stones or discarded limpet shells left behind by gulls.1 2 Next