The Dunlin is a master of the mudflats, yet its numbers are rapidly falling.

Countries & Cities · Published 15 October 2026 Swipe more like this →

In short: This small, unassuming wader is the most common coastal bird of its kind, known for its distinctive black belly and sensitive, probe-like bill. Despite their ability to gather in massive, synchronized flocks, Dunlin populations have seen a sharp global decline of 20 percent since the early 2000s.

The Dunlin, scientifically known as Calidris alpina, is a circumpolar breeder that thrives in Arctic and subarctic regions. While they are highly gregarious during the winter, often forming large, swirling flocks on coastal mudflats, their survival is increasingly threatened. In the United Kingdom, they were added to the Red List in 2021 due to a massive decrease in wintering populations. This decline is part of a broader global trend, with numbers dropping by 20 percent since the early 2000s. Habitat fragmentation, particularly for southern subspecies like C. a. schinzii, has reduced connectivity between breeding patches, leaving these birds more susceptible to the risks of inbreeding.

Physically, the Dunlin is perfectly adapted for its environment. Measuring 16 to 20 centimeters in length with a wingspan of 35 to 40 centimeters, it possesses a slightly down-curved, black bill. This is not merely a tool for picking; the tip of the bill features a soft, blood-filled covering packed with nerve endings. This sensitive probe allows the bird to locate insects, snails, and worms hidden deep within mud and sand. When feeding, they move with a characteristic 'sewing machine' motion, methodically searching for prey as the receding tide exposes the nutrient-rich mudflats.

Their life cycle is marked by impressive migratory feats and unique parental roles. While some Dunlins reside in the UK, winter populations are significantly bolstered by breeders arriving from the north. During the breeding season, they nest in shallow ground scrapes. Interestingly, while both parents incubate the eggs, the male takes on the majority of brood care, as the female often deserts the area shortly after the chicks hatch. These precocial chicks develop quickly, typically taking flight at about three weeks of age. Protecting these vital intertidal habitats remains critical for the future of this species.

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