Hudsonian Godwit

Birds arrive on the breeding grounds between late April and early June, sometimes touching down while snow still covers the tundra. The species is presumed to be socially monogamous, with pair bonds sometimes persisting between seasons. Sexual maturity is reached at approximately three years of age — late by shorebird standards — and the generation time is estimated at 7.7 years.

The male makes several scrapes in drier portions of the territory; the female selects which one becomes the nest. Nests are shallow depressions set on a dry hummock within a sedge marsh, typically tucked under dwarf birch or other low shrubs. The cup is sparsely lined with twigs, dead leaves, sedges, bog rosemary, spruce needles, grasses, mosses, and lichens — averaging about 14 cm across and 4.3 cm deep. The clutch typically consists of four eggs (occasionally two or three), described as olive-grey, pearl grey, buffy olive, or greenish, with dark speckling or brown blotches. Both parents share incubation duties for approximately 22–25 days.

Chicks are precocial — active and covered in down at hatching — and leave the nest within hours. Newly hatched chicks are capable of swimming across pools and slow-flowing streams, a useful ability in the waterlogged tundra habitats where they hatch. Both parents tend and guard the chicks, which find their own food from the start. Young are able to fly at approximately 30 days. If the first nest is lost to predation, females may lay a replacement clutch. Adults typically depart the breeding grounds before juveniles, with males leaving as early as late June — one of the earliest departures of any long-distance migrant.

The oldest recorded Hudsonian Godwit lived to at least 6 years and 1 month, based on banding data. Typical lifespan in the wild is estimated at 5–10 years, based on banding recoveries and comparisons with similarly sized shorebirds. The species' late sexual maturity — birds do not breed until around three years of age — and long generation time of approximately 7.7 years mean that individuals must survive for several years before contributing to reproduction.

The main natural mortality factors include predation on the breeding grounds (eggs and chicks are taken by Arctic foxes, ravens, and jaegers), starvation during migration if key stopover sites are degraded or unavailable, and the inherent risks of long overwater flights. Historically, market hunting in the 19th century drove the species to very low numbers; the population has never fully recovered. The combination of low reproductive rate, high dependence on a small number of staging and wintering sites, and ongoing habitat loss makes the species particularly sensitive to additional mortality from any source.

The Hudsonian Godwit is listed as Vulnerable on the IUCN Red List (2024) and as Threatened by COSEWIC in Canada (2019). In the United States, it was designated a Red Alert Tipping Point species in the 2025 State of the Birds report — a category reserved for species that have lost more than 50% of their population in the past 50 years and face ongoing steep declines. The global population is estimated at 41,000–77,000 individuals depending on the source and methodology, with BirdLife International's 2024 estimate placing it at 41,000–70,000 mature individuals.

The trend is sharply downward. Migration monitoring data from James Bay staging sites between 1995 and 2016 indicate a 6% annual decline — a cumulative loss of approximately 71% over roughly three generations. Wintering site counts at Tierra del Fuego show an estimated 4% annual decline from 2002 to 2018, equating to a 62% reduction over three generations, though numbers at Chiloé Island have been relatively stable.

The threats are multiple and interconnected. Climate change degrades Arctic and boreal breeding habitats through rising temperatures, increased fire risk, and invasive species, while also altering prey availability across the annual cycle. Unsustainable logging, mining, oil and gas extraction, hydroelectric development, and overgrazing by abundant geese — particularly in the Hudson Bay Lowlands — all degrade nesting habitat. The conversion of Great Plains wetlands removes critical spring refuelling habitat.

Wintering sites face their own pressures: human disturbance and aquaculture development (especially in Chile) threaten key sites in Tierra del Fuego and Patagonia. The species' entire global population passes through only a handful of staging and wintering sites, making it acutely vulnerable to localised habitat loss or disturbance at any one of these bottlenecks. Historically, market hunting in the 19th century decimated the species. It is now protected in the USA but may still be hunted in parts of Central and South America.

The Black-tailed Godwit is the Hudsonian's closest lookalike in structure, but the two are cleanly separated in flight by underwing colour alone: the Black-tailed shows a white underwing and broad white wing bar, while the Hudsonian's axillaries and wing linings are sooty black. At rest, the Black-tailed's bill is straighter and the legs are longer. The Bar-tailed Godwit is stockier, shorter-legged, and has a more strongly upturned bill; in flight it shows a barred tail, streaked rump (not clean white), and pale underwing. The Marbled Godwit of North America is larger, warm buffy-brown overall, and shows cinnamon wing linings in flight — the opposite of the Hudsonian's black underwing.

In the field, the Hudsonian Godwit's black underwing is the single most reliable separator from all congeners. At rest, the combination of slightly upturned bicoloured bill, pale supercilium, and (in breeding plumage) heavily barred chestnut underparts is distinctive. Non-breeding birds are plainer and can be confused with Black-tailed Godwit, but the bill shape — more strongly upturned in the Hudsonian — and the smaller overall size are useful supporting features. In North America, the Willet is sometimes confused with godwits at a distance, but is shorter-billed, shorter-necked, and shows a bold black-and-white wing pattern rather than the godwit's narrow white stripe.

Courtship begins as soon as birds arrive on the breeding grounds, even when snow still covers the tundra. The male's aerial display is one of the most elaborate of any North American shorebird. He spirals erratically upward on rapidly beating wings, then switches to an exaggerated 'butterfly' display: wings beating slowly above body level, the bird rocking side to side while singing continuously. The display culminates in a dramatic plummet toward the ground, pulling out about 9 metres (30 feet) above the surface, then gliding to perch atop a stunted spruce or hummock where he fans his tail and raises one wing to show the black-and-white pattern.

Males also dive toward females on the ground, opening the wings at the last moment to produce a winnowing sound. Once paired, both sexes may perform joint display flights together on trembling, downward-arched wings — a behaviour that appears to reinforce the pair bond. The male prepares several scrapes in drier parts of the territory, and the female makes the final selection of which scrape will become the nest. Pair bonds can persist through re-nestings within a season and sometimes carry over from one year to the next, though the species is presumed to be socially monogamous rather than strictly mate-faithful across all years.