Lesser Yellowlegs

A backlit shorebird with a geolocator tag perches in a spruce tree
A banded Lesser Yellowlegs atop a black spruce on Joint Base Elmendorf-Richardson (JBER). A metal band, a dark green color band, an alpha character leg flag and in some instances, a 4g Argos PinPoint satellite-GPS unit are deployed on captured adults. 📷 USFWS/Alec Blair

I read that Lesser Yellowlegs are under-studied on their breeding grounds because they nest in inhospitable environments: difficult to access and mosquito-ridden, boreal bogs. That doesn’t sound like the most romantic fieldwork location, and those conditions definitely weren’t how I imagined wild Alaska prior to visiting the state. However, where the birds are, the birders are — and in this case, the ornithologists.

wood frog in someone’s hand
Top: Wood Frog (Lithobates sylvaticus; right) are common across boreal wetlands in Southcentral Alaska. Bottom: One of 35 species of mosquito found in Alaska.📷:USFWS

The Bird

The Lesser Yellowlegs (Tringa flavipes) is a shorebird (sandpiper, specifically) with long yellow legs and a relatively long neck. It’s an elegant bird that people describe as both “dainty” and “slender”; certainly not a species you would expect to migrate tens-of-thousands of kilometers a year from the northern boreal forests of Alaska and Canada to the wetlands and coastlines of Central and South America and the Caribbean.

A lesser yellowlegs with leg bands perches on a branch
A nesting adult Lesser Yellowlegs perched on top of a mossy black spruce snag on JBER. Parents will take turns foraging and incubating. Incubation lasts 22–23 days and precocial young (hatched in an advanced state and able to feed themselves) are defended by the male parent until fledge.

The Lesser Yellowlegs black bill isn’t as exaggerated as some shorebirds, but what it may lack in looks, it makes up for in vocal performance. The Lesser Yellowlegs is an extraordinarily audible bird. Anytime we were within a quarter mile of a nest or brood, we would hear its alarm calls. The Lesser Yellowlegs specialize at standing atop a black spruce and yelling until any threats are out of its territory.

Canadian ornithologist William Rowan perfectly described this behavior nearly a century ago in 1929; “they will be perched there as though the safety of the entire universe depended on the amount of noise they made.”

Because of their conspicuous nature, nesting season is the perfect opportunity for ornithologists to study the breeding biology of these birds.

The Plight of Lesser Yellowlegs

Since the 1970s, the Lesser Yellowlegs has experienced a precipitous population decline. In Alaska alone, the population has seen a 5.3% to 9.2% decline per year since 2003 (Handel and Sauer 2017). The factors contributing to this decline are complex and include wetland conversion, agricultural pollution, climate change, and the most recently identified threat — harvest. The movement data collected by the GPS units provide conservationists an understanding of the proportion and timing of Lesser Yellowlegs traveling through regions where shorebird harvest is practiced, in turn leading to the development of conservation strategies for the species.

“This is a frequently harvested shorebird species for both subsistence and sport hunting on their wintering grounds; we want to understand how different breeding populations may be disproportionately influenced.” — Laura McDuffie

A range map for the lesser yellowlegs
Map represents the breeding, non-breeding, and migratory range of the Lesser Yellowlegs. Occupancy data derived from Cornell Lab of Ornithology eBird data.

The Research

The goal of fieldwork this season was to understand the species annual migratory movements by deploying 4g Argos PinPoint satellite-GPS units on a small sample of breeding adults. Birds were trapped using mist nets, which consist of a fine mesh meant for entangling a bird without harm. Upon capture, morphometrics (i.e. wing, head and tarsus length) and biological samples (i.e. blood, feather, and nail clippings) were collected from each captured bird.

A biologist takes measurements of a lesser yellowlegs in her hand
Laura reads the tarsus measurement of a Lesser Yellowlegs captured on the Anchorage Coastal Wildlife Refuge.

Of the 29 adults captured in 2019, 17 received Argos Pinpoint satellite-GPS units. This was the second of three field season deploying GPS, of which, 19 tags were deployed in 2018 and 12 in 2020 across Anchorage and JBER. However, this study involves collaborators that banded Lesser Yellowlegs in Kanuti National Wildlife Refuge, Alaska; Yellowknife, Northwest Territories; Churchill, Manitoba; James Bay Ontario and Mingan Archipelago, Quebec. In total, 110 adult Lesser Yellowlegs are equipped with GPS units, which track their movements at defined intervals during the annual migratory cycle.

Each GPS unit is attached to a bird using a leg-loop harness method. The unit sits on the lower back and is anchored in place by silicon loops around the bird’s hips. Units are adjusted to each individual bird to insure a safe, least-invasive fit. Deploying transmitters on the birds allows biologists to better understand how the species is using the landscape.

Two biologists affix a geolocator tag to a lesser yellowlegs
Laura adjusting a leg-loop harness prior to releasing the bird.

“GPS units are accurate to about 10 meters in optimal conditions, because of this, I can determine where Lesser Yellowlegs are stopping to refuel during migration, the types of habitats they prefer, and their probability of occurrence within shorebird harvest regions.” — Laura McDuffie

The Crew

I was fortunate to spend a week studying Lesser Yellowlegs with two young, but very seasoned ornithologists: Laura McDuffie and Will Britton.

Biologist Laura McDuffie
Biologists Laura McDuffie and Will Britton
Laura McDuffie (top), a previous UAA graduate student and current USFWS term biologist and Will (bottom) a USFWS seasonal avian technician.

At the time of this research, Laura was working towards her Masters at the University of Alaska Anchorage while simultaneously holding a biologist position with US Fish & Wildlife Service Migratory Bird Management program. Will was a field technician who has traveled cross-country the past five years working on different bird projects from hawk watches to shorebird surveys. With assistance from the Alaska Department of Fish and Game Threatened, Endangered, and Diversity Program biologists, Laura and Will monitored and trapped Lesser Yellowlegs in Anchorage. Additionally, since the projects inception in 2016, the Department of Defense-United States Air Force 673 CES/CEIEC have provided financial and logistical support for fieldwork on Joint Base Elmendorf-Richardson (JBER).

The Trials and Tribulations

Perhaps a poorly made soap opera could have served better than a written story to speak towards the week of fieldwork I experienced.

On the second day, we started our work with a visit to a local lake. A newly established Lesser Yellowlegs nest of four eggs promised our best chance of trapping adult birds.

Lesser yellowlegs nest and eggs
A Lesser Yellowlegs nest lies among the Labrador Tea (Rhododendron tomentosum) and Dwarf Birch (Betula nana) at a bog on JBER.

An early morning started beneath a restless Alaskan sun. After shuffling through bog water, Laura arrived first to the nest and let out an audible sigh upon identifying it. No trace of eggs — not even small fragments of cracked shells. She immediately traversed through the wetland over to the nearby game camera she positioned by the nest just several days prior. She scrolled through the SD card to see what may have been recorded. Unsurprising footage: a couple of moose walked by, the parents exchanged position on the nest, and then we saw it: a bear. A black bear that had an indulgent meal. The parents wouldn’t be returning to the nest. Yet, we could still hear and see them circling the site. Their alarm calls began to reform in my head as cries. A sobering moment for us all, we realized we had just missed it, too — the bear had visited that very same morning.

Recomposed, we jumped back into our seats of the enormous, emblematic USFWS truck aptly named “Goose Truck” and pressed on. Laura and Will are resilient: realizing you lost one of your nests to a black bear by about 45 minutes must be tough. I was upset about it and I didn’t even know the nest existed until Laura had debriefed me on the ride over. Every day flowed along this way — loose plans to start, then spontaneity and unpredictability as the environment really took the reins from us.

Late in the week we recaptured a Lesser Yellowlegs banded in 2018 at the Anchorage Coastal Wildlife Refuge. We had been trying to catch this bird for two long days consisting of waiting, swatting mosquitos, and chatting about rare bird sightings. Our patience paid off and we recapture the bird and replace the GPS unit with a new one. This bird provided the first results of wintering site fidelity.

Biologists remove a lesser yellowlegs from a mist net
Will and Laura untangle a Lesser Yellowlegs carrying a GPS unit deployed in 2018. The old unit was removed and replaced in hopes that the consistency of individual birds’ migratory movements can be revealed.

The week of thrills involved a range of highs and lows; fitting for a project centered on a bird with so much personality. Moose, bear and porcupine sightings, run-ins with both Short-billed Dowitcher and Bonaparte’s Gull broods, some uplifting trappings, and some heartbreaking misses.

Dowitcher chicks at the edge of a tundra pond
Moose foraging on green vegetation
Bonaparte’s gull and chicks
Short-billed Dowitcher chicks (top) huddle together in the short grasses of the Boreal. Moose run-ins (left) can be frequent on JBER. A Bonaparte’s Gull (right) protects its chicks as they forage around Otter Lake, JBER.

Countless hours of fieldwork in some pretty unkind Alaskan terrain could afford a person a valid amount of superiority, yet Laura and Will never failed to come down to where I stand as a novice birder. They gave me every opportunity to see the passion and excitement that lies within their work and its importance: to understand the remarkable and demanding process of the life and movements that the Lesser Yellowlegs participate in each year. To be out-waited (and sometimes outwitted) by a Lesser Yellowlegs parent who recognized our potential threat to its brood. To gain empathy and humility when a nest is depredated or abandoned.

After I shared a photo of the bird with a caption including its name, a friend asked me, “why is it lesser?” The immediate answer is easy: its distinction from its larger counterpart — the Greater Yellowlegs — to whom it is similar in appearance but surprisingly unrelated (bird naming seems to be a sport of its own).

“Greater” vs. “Lesser” is common practice in species naming, but, as I thought more about it, I began to take some offense on behalf of the bird. I questioned whether this branding is a disservice to the bird: to blanket a species with a title that intentionally minimizes its size and, inadvertently, its efforts. This is inconsequential within the scientific community and to challenge that naming may be laughably unnecessary and contrarian. Yet, it is a name that makes the bird seem inferior. It reduces impressive feats like its migratory route, to an illusion about its stature. But its alarm call is hardly lesser, nor its aggressive protective tendencies.

Perhaps, even more poetically, the label “lesser” could serve as a symbol for the current downward trend of the bird’s population and its potential peril from over-harvesting. The threats to this shorebird and the degradation of its habitats are complex, multifaceted issues that reach across borders and cultures just like its migration. Efforts like those of Laura and her collaborators attempt to explain the human relationship and impact on the bird and how we may engage with its global conservation.

Lesser yellowlegs chasing a red-necked phalarope
A Lesser Yellowlegs (right) chases off a Red-necked Phalarope (left) while foraging at a lake on Joint Base Elmendorf-Richardson in Anchorage, Alaska. Lesser Yellowlegs can be territorial, especially during the breeding and incubation periods.

Written by Alec Blair, 2019 Directorate Fellow for Migratory Birds Management in Anchorage, Alaska. Compiled by Katrina Liebich, Alaska Digital Media Manager for External Affairs, and Peter Pearsall, Communications Specialist for External Affairs/Migratory Birds.

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