For an olive-sided flycatcher, migration could be a marathon. A number 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 doable,” mentioned 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 mentioned. So in 2013, she and her colleagues got down to unravel it by monitoring the birds. They hoped that figuring out the important stopover websites would possibly present clues about why olive-sided flycatcher populations have been declining and what may be wanted to save lots of them, together with the place consultants ought to goal their conservation efforts.
The analysis proved to be tougher than they’d bargained for. Olive-sided flycatchers usually breed in buggy bogs. They perch on the tops of bushes. And they’re elusive, sparse on the panorama and troublesome to catch. “After the primary yr of combating this venture, it turned actually, actually clear why no person of their proper thoughts would wish to attempt to research this fowl,” Dr. Hagelin mentioned.
Right here’s what it took for scientists to get the info:
Make a lure
Olive-sided flycatchers may be extremely delicate to incursions into their territory, so the scientists lured the birds with pretend avian rivals. They purchased picket fowl decoys on eBay, after which painted white patches on the flanks to duplicate the flash of white feathers that males usually present once they’re agitated. “It’s form of an extended distance sign of ‘Preserve away’ or ‘That is my spot,’” Dr. Hagelin mentioned.
Catch a flycatcher
The researchers connected the decoys to small bushes or tied them to massive sticks that have been positioned upright within the smooth floor. They strung up positive 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 will fly on the picket interloper and wind up of their nets. Some birds did simply that, responding shortly to the decoy. However typically it might take hours to catch only one flycatcher. “Possibly two, if we have been fortunate,” Dr. Hagelin mentioned.
Connect a tag
The researchers used clear plastic wire — designed for making beaded jewellery — to trend tiny flycatcher harnesses, every bearing a geolocator tag. As soon as they’d 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 recurrently 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 information.
Do it once more a yr later
To obtain the info, the researchers needed to recapture the identical birds the following summer time. “Recovering this data added to my grey hairs,” Dr. Hagelin mentioned. 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 likely to exit or enter the nest and the way they’re transferring via the bushes,” Dr. Hagelin mentioned. “So you may put a internet in the best way 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 information in any respect for causes the scientists nonetheless don’t perceive. “That was actually devastating,” Dr. Hagelin mentioned.
“However all was not misplaced,” she added. The geolocator information pointed to 13 essential stopover websites, from Washington to southern Peru, plus three principal wintering areas in South America, the researchers reported in 2021. Tagging know-how has improved, so scientists with an urge for food for flycatcher catching might now concentrate on accumulating extra detailed information on these places. “Am I the particular person to do it?” Dr. Hagelin mentioned. “Possibly if I had the funding.”
