How to Track a Songbird from Alaska to Peru

For an olive-sided flycatcher, migration is usually a marathon. A few of the soot-colored songbirds journey greater than 15,000 miles a yr, winging their manner from South America to Alaska after which again once more. It’s a dizzyingly lengthy journey for a fowl that weighs simply over an oz..

“Alaska populations of olive-sided flycatchers are simply on this razor-thin margin of what’s biologically attainable,” stated Julie Hagelin, a wildlife analysis biologist on the Alaska Division of Fish and Recreation and a senior analysis scientist on the College of Alaska Fairbanks.

To outlive the lengthy journey, the birds want secure locations to relaxation and refuel. However the places of those “little utopias” have been a thriller, Dr. Hagelin stated. So in 2013, she and her colleagues got down to unravel it by monitoring the birds. They hoped that figuring out the crucial stopover websites would possibly present clues about why olive-sided flycatcher populations have been declining and what may be wanted to avoid wasting them, together with the place specialists ought to goal their conservation efforts.

The analysis proved to be harder than that they had bargained for. Olive-sided flycatchers typically breed in buggy bogs. They perch on the tops of timber. And they’re elusive, sparse on the panorama and tough to catch. “After the primary yr of fighting this undertaking, it grew to become actually, actually clear why no person of their proper thoughts would wish to try to research this fowl,” Dr. Hagelin stated.

Right here’s what it took for scientists to get the information:

Make a lure

Olive-sided flycatchers may be extremely delicate to incursions into their territory, so the scientists lured the birds with faux avian rivals. They purchased wood fowl decoys on eBay, after which painted white patches on the flanks to copy the flash of white feathers that males typically present after they’re agitated. “It’s type of an extended distance sign of ‘Maintain away’ or ‘That is my spot,’” Dr. Hagelin stated.

Catch a flycatcher

The researchers hooked up the decoys to small timber or tied them to massive sticks that have been positioned upright within the smooth floor. They strung up high quality mist nests and performed flycatcher calls from audio system hidden within the bushes beneath the decoy. The scientists hoped that if an actual flycatcher was within the space, it might fly on the wood interloper and wind up of their nets. Some birds did simply that, responding shortly to the decoy. However generally it may take hours to catch only one flycatcher. “Perhaps two, if we have been fortunate,” Dr. Hagelin stated.

Connect a tag

The researchers used clear plastic wire — designed for making beaded jewellery — to vogue tiny flycatcher harnesses, every bearing a geolocator tag. As soon as that they had a fowl in hand, they slipped the loops of the harness over its legs, positioning the tag in opposition to its decrease again.

When the birds flew south for the winter, the geolocator tags usually recorded the sunshine ranges and the time, permitting the scientists to estimate every fowl’s approximate latitude and longitude. In later years of the research, they transitioned to utilizing GPS tags, which might present extra exact location knowledge.

Do it once more a yr later

To obtain the information, the researchers needed to recapture the identical birds the subsequent summer time. “Recovering this data added to my grey hairs,” Dr. Hagelin stated. The second time round, the birds have been warier and fewer attentive to the scientists’ trickery, so the researchers spent hours watching flycatcher nests.

“You can begin to see patterns like places or instructions that the birds are inclined to exit or enter the nest and the way they’re shifting by the timber,” Dr. Hagelin stated. “So you may put a internet in the way in which and hope you’ll catch them that manner.”

Cross your fingers

Over the course of the five-year research, the researchers managed to deploy 95 tags. They recovered 17 geolocator tags however simply 5 GPS tags — and three of the GPS tags failed, offering no knowledge in any respect for causes the scientists nonetheless don’t perceive. “That was actually devastating,” Dr. Hagelin stated.

“However all was not misplaced,” she added. The geolocator knowledge pointed to 13 essential stopover websites, from Washington to southern Peru, plus three fundamental wintering areas in South America, the researchers reported in 2021. Tagging expertise has improved, so scientists with an urge for food for flycatcher catching may now deal with accumulating extra detailed knowledge on these places. “Am I the individual to do it?” Dr. Hagelin stated. “Perhaps if I had the funding.”