Whimbrel Wanderings
From Kanuti Refuge to the coast of South America, this bird is a travel expert
Hundreds of miles inland from the icy waters of the Bering Sea and Arctic Ocean, a shorebird’s piping whistle calls across the boreal wetlands of interior Alaska. Spiraling and singing, he performs a dramatic aerial display for his potential mate, a female whimbrel recently arrived from wintering in South America. The midnight sun skims across the horizon as they begin their summer life together on Kanuti National Wildlife Refuge, at the edge of the Arctic Circle.
For those of us with wanderlust, the incredible long-distance migration of the Pacific Flyway whimbrels is an inspiration. For biologists, until recently, it was also a bit of an enigma. Some had sighted whimbrels banded at Chiloe Island off the coast of Chile arriving in the north and west of Alaska. They had also seen banded whimbrels stop over at coastal sites along the flyway. But that left many thousands of mystery miles in between…
A small number of Alaska-breeding whimbrels from Kanuti Refuge and the Colville River fitted with satellite transmitters between 2009–2015 help us better understand — and appreciate — this shorebird’s far-flung wanderings, and how we are all connected to its fate.
Finding Numeniini: a tundra patch surprise
Kanuti biologist Chris Harwood remembers hearing the arrival of a whimbrel during his first “spring out” at Kanuti Lake cabin within the refuge.
“I arrived by ski plane in late April, and it was my first time to visit during this part of the year. It is a really special season, when the ice breaks up, the birch trees begin to leaf out, and the migratory birds arrive and begin their mating displays.”
As Harwood watched the boreal forest emerge from winter, he also had time to explore beyond the woods into patches of tundra south of the lake. Beginning the first week of May, he heard the first arrivals of a whimbrel and Hudsonian godwit.
Intrigued, he visited the tundra patch many times over the next two weeks and watched as a few dozen birds courted and began to nest. Using a survey method known as “point counts” over the next two months, Harwood recorded a population of breeding whimbrels and godwits — something of surprise in the Interior’s largely unsurveyed lowlands.
“While we knew of a previous whimbrel pair near the Kanuti Lake cabin, we didn’t expect to find this larger population within the boreal wetlands. Both godwits and whimbrels tend to nest beyond treeline on open tundra or in more subalpine areas in the Interior like the Alaska Range.”
Whimbrels and Hudsonian godwits belong to a group of shorebirds collectively known as Numeniini. Though they are widespread around the world, several species are in decline or face critical threats like diminished and degraded habitats. Learning more about their migrations can help global partnerships target areas important for Numeniini conservation.
The refuge’s boreal tundra patch of whimbrels piqued the interest of U.S. Geological Survey researchers preparing to study the migration of whimbrels further north at the Colville River, 20 miles from the Arctic Ocean. Harwood’s “spring out” explorations led to the inclusion of the Kanuti birds in the first study of Pacific Flyway whimbrel migration using tiny satellite transmitters to track locations throughout the annual cycle.
Whimbrel #03’s Itinerary: Kanuti to Ecuador and back
One year after 15 Kanuti whimbrels received their transmitters, Harwood had returned to Kanuti Lake. It was the 14th of May when he received a call from a colleague in Anchorage, who was tracking the return migration in real time using satellite data, to “be on the lookout for male #03,” a whimbrel that had just passed through southcentral Alaska after spending the winter in tropical Ecuador.
Sure enough, Harwood located male #03 the next day on the same patch of tundra where he had nested the previous summer (named for the numbered flag attached during initial capture and banding). His return completed an annual cycle that contributed new information for biologists beginning to fill in a picture of migration for Pacific Flyway whimbrels.
Flight Plan filed for Whimbrel 03:
Early July: leave Kanuti breeding grounds
Pre-Migration Fattening:
Travel to Yukon Delta National Wildlife Refuge in western Alaska for a few days, then to the north coast of the Alaska Peninsula for a few weeks;
Early August: Fly 85 hours across the Pacific Ocean to El Carrizo and then to Los Mochis, Mexico.
Mid September: Arrive at Puerto del Morro, Ecuador for the boreal winter.
Early April: Depart Ecuador for Kern National Wildlife Refuge and then to Visalia, California.
Early May: Depart California and fly 57 hours to southcentral Alaska.
Mid May: Arrive at Kanuti National Wildlife Refuge
Mapping Migration
As #03 returned to Kanuti, biologists prepared to give whimbrels breeding on the Colville River their first satellite transmitters.
Whimbrel #T6, a star of the study from the Colville River, continually returned to the same site for the five years his transmitter tracked locations (see below, map left). His annual itinerary southbound included pre-migration fattening weeks at Selawik and Yukon Delta National Wildlife Refuges, before stops in Mexico and Peru on the way to his boreal winter home in Chile.
Overall, biologists tracked thirty-one Alaska-breeding whimbrels in their migration, some over several years (see below, map center and right).
Their results mapped here fill in some of the mysteries of Alaska-breeding whimbrels’ long-distance travel along the Pacific Flyway:
- Though they nest relatively close to one another on the summer Arctic tundra (some within 300 feet), their final non-breeding coastal destinations spread out over 70 degrees of latitude, from Mexico to Chile.
- Collectively, this small group of whimbrels touched the coast of every country along the Pacific Flyway once they left their breeding grounds in Alaska.
- When departing from Kanuti and Colville to begin their southbound flights, the whimbrels lingered in other areas of coastal Alaska for several weeks to fuel up before their long flights, including several National Wildlife Refuges: Selawik, Innoko, Koyukuk, Yukon Delta, Togiak, and Alaska Peninsula.
- Some of their tracked non-stop flights are among the longest recorded for land birds (e.g. about 5400 miles between Santo Domingo Chile and agricultural lands near Calipatria, California).
“As a refuge biologist, it’s rewarding and a point of pride to see how important refuges, especially Alaska refuges, are in the annual cycle of Whimbrels.” Harwood reflected.
“However, this study really shows how much of the eastern Pacific Flyway Whimbrels rely on. Their conservation is a Western Hemispheric challenge, not just a Kanuti or Alaska one. We’re all connected.”
The results of this study, including the maps for #T6 and the comprehensive results of southbound and northbound migration, recently published in the Journal of Field Ornithology:
Ruthrauff, D.R., C.M. Harwood, T.L. Tibbitts, N. Warnock, and R.E. Gill. 2021. Diverse patterns of migratory timing, site use, and site fidelity by Alaska-breeding Whimbrels. Journal of Field Ornithology. https://doi.org/10.1111/jofo.12365.
Story by Lisa Hupp, Communications Coordinator for Alaska Refuges, based on article by Chris Harwood, Wildlife Biologist for Kanuti National Wildlife Refuge.
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