Stilt Sandpiper

Males arrive on the Arctic breeding grounds a few days ahead of females in late May to early June and immediately begin establishing territories. Laying typically starts in the first half of June. The male makes several scrapes in the tundra — usually on a dry low ridge, raised hummock, or top of a sedge hummock, often surrounded by water or wet ground — and the female selects one as the nest site.

The nest is a shallow depression, averaging about 10.4 cm across and 3 cm deep, lined with willow and birch leaves, grasses, sedges, cotton grass, horsetail, mosses, and lichens.

Clutch size is typically 4 eggs (range 2–5), described as light green to olive green, heavily dotted with dark brown. Both parents share incubation duties over approximately 19–21 days: the female incubates at night, the male during the day. Nests are usually at least 100 m apart; in prime habitat at Churchill in the 1960s, average internest distance was 300–400 m.

Chicks are precocial and leave the nest within a day of hatching, finding all their own food from the start. Both parents initially tend and defend the brood, but the female typically departs when the chicks are only 2–3 days old. The male remains until the chicks are 10–14 days old, then also departs before the young can fly well. Young fledge at approximately 17–18 days. Each pair raises only one brood per season, and the species does not generally breed until two years old.

The mating system is monogamous, and some pairs may mate for life. Breeding site fidelity is high: studies at Churchill found that up to 50% of pairs at a given location return to breed in consecutive years. Established pairs with high site fidelity may dispense with courtship displays entirely, going straight to nest preparation on arrival.

The typical lifespan of a Stilt Sandpiper in the wild falls between 5 and 9 years, though individuals regularly exceed this. The oldest recorded individual was at least 11 years and 1 month old when recaptured and rereleased during banding operations in Texas, placing it among the longest-lived small shorebirds on record.

Annual survival rates are not well documented for this species, but the demands of long-distance migration — including the overwater crossing of the Caribbean — represent the most significant mortality risk outside the breeding season. Collision with power lines during migration is a documented cause of death. On the breeding grounds, nest predation and habitat degradation (particularly from Snow Geese) reduce productivity, and the species does not breed until two years old, meaning young birds must survive two full migration cycles before contributing to the population.

The high breeding site fidelity documented at Churchill — with up to 50% of pairs returning in consecutive years — suggests that experienced adults have relatively high annual survival once they reach breeding age. This is consistent with the life-history strategy of a long-distance migrant that invests heavily in each breeding attempt.

The Stilt Sandpiper is currently listed as Near Threatened on the IUCN Red List (2024 assessment), with a global population estimated at approximately 1.2 million mature individuals. The Canadian population alone is estimated at 500,000–1,000,000 adults, giving Canada an exceptionally high responsibility for the species' global survival.

The population trend is declining. The 2025 State of the Birds report (USA) lists the Stilt Sandpiper as an Orange Alert Tipping Point species. This designation means it has lost more than 50% of its population over the past 50 years and has shown accelerated declines within the past decade. Partners in Flight rates it 15 out of 20 on the Continental Concern Score. The most dramatic documented decline occurred at Churchill, Manitoba: breeding density fell from 12–16 pairs per 100 ha in the 1960s to just 2–4 pairs per 100 ha in the 1990s — a reduction of roughly 90% over 30 years. However, populations in Alberta and at Prudhoe Bay, Alaska appear to be increasing, suggesting a possible westward shift in breeding distribution rather than a uniform collapse.

The primary threat on the breeding grounds is habitat degradation caused by overabundant Snow Geese and Canada Geese, which graze heavily on grasses, sedges, and rhizomes, destroying tundra structure. At Churchill, hatching success fell from 91% of nests in the 1960s to 68% in 1992–1996, directly linked to goose-driven habitat loss.

Beyond the goose problem, several further pressures compound the decline. Warming temperatures are drying fens and driving shrub and tree encroachment through isostatic rebound, shifting prey availability on the breeding grounds. Petroleum and gas development threatens key breeding areas in Alaska, while on migration and wintering grounds the main risks are loss and drainage of freshwater wetlands in South America and hunting in the Caribbean. Collision with power lines is an additional documented mortality cause. The species is listed as a USFWS Bird of Conservation Concern. No specific management plans are currently in place.

Start with the legs: long, greenish-yellow, and immediately visible at distance, they lift the bird noticeably higher than a Dunlin or Pectoral Sandpiper. Add a drooping bill tip and a plump belly and you have a distinctive hunched, front-heavy silhouette unlike any other sandpiper. The bill droops where a yellowlegs' bill is straight.

In breeding plumage (April–August), identification is straightforward: the combination of chestnut cheek, bold white supercilium, and heavily barred underparts is unique among North American shorebirds.

Non-breeding and juvenile birds require more care. Focus on the persistent bold white supercilium (present year-round), the long drooping bill, and the greenish-yellow legs. Juveniles show a scaly, textured upperpart pattern with neat pale feather edges.

The most common confusion species are the two dowitchers (Short-billed and Long-billed), which share the sewing-machine feeding action. Dowitchers have shorter, greenish-grey legs, a straight bill, and a bold white wedge up the back visible in flight — the Stilt Sandpiper's back is plain. Lesser Yellowlegs shares the long legs and upright stance but has a straight bill, yellow (not greenish-yellow) legs, and spotted rather than barred underparts in breeding plumage.

In flight, look for the plain wings (no wingbar), white rump, grey tail, and long legs projecting well beyond the tail tip. The hump-backed silhouette is distinctive. The call — a low, soft "tew" — is quieter and less carrying than a yellowlegs' sharp whistle.

The male's courtship display is built around a deep-V wing posture and a plummeting dive that sets it apart from the more horizontal display flights typical of other Calidris-group sandpipers. He pursues the female in the air, flies ahead of her, then raises his wings sharply over his back and plummets toward the ground while singing continuously and rocking from side to side. A lower-altitude display — shallow wingbeats while circling the female — may alternate with the plummeting dive.

Males arrive on the breeding grounds a few days before females and begin displaying immediately, calling incessantly from the air throughout the long Arctic day. The display song is a guttural, continuous vocalisation: a series of musical, low "twew" notes interspersed with coarse calls and whines, delivered at full volume during the aerial display. This performance serves simultaneously as courtship to the female and territorial advertisement to rival males.

For details of nest construction, clutch size, incubation, and breeding site fidelity, see the nesting and breeding section above.