Joined: Wed Jul 29, 2009 9:44 pm
Location: Milton, Pa.
|Osprey tracking project takes tragic turn
Published Date Written by Adam Drapcho
HOLDERNESS — Iain MacLeod, executive director of the Squam Lakes Natural Science Center, knew that tracking juvenile osprey on their first fall migration was not an activity for the faint of heart. Last year, he placed a transmitter on a young female, only to watch remotely as she fell victim to stormy weather and drowned in the Caribbean. Still, that experience didn't make it easy for MacLeod earlier this week when data from the transmitters on two locally-hatched birds started to tell traumatic tales.
MacLeod placed the transmitters on three local birds earlier this year as part of Project Osprey Track, a collaboration involving the Squam Lakes Natural Science Center, Public Service of New Hampshire and Dr. Richard "Rob" Bierregaard, a research professor with the University of North Carolina. Several birds have been affixed with transmitters, which send regular updates regarding the bird's location, altitude, direction and speed. Local birds involved in the project include "Art," an adult male who spends his summers in Bridgewater, and siblings "Chip" and "Jill," who hatched this spring in a nest in Tilton near the J. Jill building.
MacLeod is keeping a blog of the birds' progress, which can be found through the Natural Science Center's website, http://www.nhnature.org.
As expected, the veteran "Art" made his migration successfully and without drama. His transmitter shows him to be cruising through a remote part of Venezuela featuring lots of marshes and rivers, a great place for a fish-eating birds to spend the winter.
For "Jill" and "Chip," though, the picture is much darker. First-year ospreys have a low survival rate for their first migration — less than 50 percent. Those that avoid disaster will spend two years in South America, then, once they reach sexual maturity, they'll return to North America to find a mate and establish their own territory. Part of the goal in placing transmitters on young birds was to learn more about this process.
"Jill" seemed to be making a picture-perfect migration, making the flight from Tilton to South America — a voyage of 3,500 miles — in 25 straight days of flying. Once she passed the most treacherous portion, the open-water flight from Haiti to Columbia, MacLeod was able to breathe a sigh of relief. However, it seemed that danger was still waiting for "Jill." After making landfall in South America, she continued flying south, some 835 miles, until reaching a very remote part of the Amazon rain forest. The first sign of trouble was on October 6 and 7, when her transmitter kept reporting the same, static location. Weather reports showed storms over that location at that time, so MacLeod held out hope that she had found a good place to wait out the wind and rain. However, the sun is shining again on Brazil, and the transmitter hasn't send another signal.
"We haven't gotten a peep from Jill," said MacLeod. "I'm pretty sure we've lost her." While he'll never be certain of her fate, he suspects she fell victim to predation. Osprey are known to fall prey to larger raptors, owls and eagles, especially. She also could have been killed by an opportunistic mammal, such as a jaguar or other large cat. "There's all kinds of stuff in the jungle down there," he said. "I think she ran out of luck."
Although "Chip" is still alive, it appears, MacLeod isn't hopeful for his survival, either. "Chip's" migration was an odd one from the beginning. He set out earlier than most osprey but stalled, for more than a month, along the Narragensett River in Rhode Island — he was still there by the time "Jill" reached Colombia. Then, on October 7, he finally headed off again, choosing a due south course that took him over the coastal waters of the Atlantic Ocean. That evening, the data suggests, he landed on a ship to spend the night. Unfortunately for him, the ship was headed east, and he was 300 miles off the coast by the morning of Oct. 8.
"Unfortunately, Chip has made terrible decisions," said MacLeod. The data seems to show that "Chip' has flown from the first ship to another, then to a third ship. "All of the boats have been in the completely wrong direction." The most recent data showed "Chip" more than 1,000 miles from the North Carolina coast.
If he is to survive, "Chip" will have to see his fortunes completely reversed. "The only hope he has is that he'll jump on another boat heading back the other way."
Adding to MacLeod's angst is the thought that "Chip" likely hasn't eaten in a few days. Osprey aren't particularly adept at catching fish in open sea, so he'd have to find a school of fish that was near the water's surface at a time when the ocean was particularly placid. Osprey aren't able to eat while on the water or while flying, so "Chip" would then have to have a ship to land on while he ate the fish.
A last hope — and it's about as long as odds get — is that "Chip" is able to endure the eastward journey, somehow finding enough food to survive, and make landfall in Africa, where European ospreys spend their winters. While that's a terribly unlikely circumstance, it would surely make "Chip" legendary among biologists, who would watch with fascination as "Chip" decides what to do next. "It would be an amazing thing, but a big stretch," said MacLeod. That being said, "Chip's" antics are already well outside of the parameters of what MacLeod or Bierregaard have observed of osprey behavior.
"Chip is breaking the mold in extremes," MacLeod said.
Despite the outcome, MacLeod doesn't regret participating in the osprey-tracking project. "It's been sad, but it's been fascinating (to see) just how wrong a migration can go." The data also shows just how hard the birds struggle every year, and why so few of them survive their first migration.
MacLeod will continue to watch Art's movements this winter, as well as those of other birds in the project. Next year, he expects to place transmitters on at least four more local birds. "I think this technology teaches amazing things that we would never know about ospreys
Life is so fragile enjoy it while you can