The dunlin (Calidris alpina) is a small wader, formerly sometimes separated with the other "stints" in the genus Erolia. The English name is a dialect form of "dunling", first recorded in 1531–1532. It derives from dun, "dull brown", with the suffix -ling, meaning a person or thing with the given quality.
It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East. Birds that breed in Alaska and the Canadian Arctic migrate short distances to the Pacific and Atlantic coasts of North America, although those nesting in northern Alaska overwinter in Asia. Many dunlins winter along the Iberian south coast.
An adult dunlin in breeding plumage shows the distinctive black belly which no other similar-sized wader possesses. The winter dunlin is basically grey above and white below. Juveniles are brown above with two whitish "V" shapes on the back. They usually have black marks on the flanks or belly and show a strong white wingbar in flight. The legs and slightly decurved bill are black. There are a number of subspecies differing mainly in the extent of rufous colouration in the breeding plumage and the bill length. Bill length varies between sexes, the females having longer bills than the males. On the tip of the Dunlin's bill is a soft covering that fills with blood and with many nerve endings, forming a sensitive probe that is used to locate invertebrate prey in mud and sand. Although the bill can look sharp-pointed in dead specimens, in life it is blunt.
Dunlin are small migratory waders, however they show strong philopatry with individuals of the Southern Dunlin (Calidris alpina schinzii) in Sweden and Finland returning to, or very close to, their natal patches. Habitat fragmentation has reduced the availability of habitat patches to these birds through reducing patch size and increasing patch isolation. This reduced connectivity between patches has reduced the movements of Dunlin leaving them more susceptible to inbreeding in these locations. Future management for the conservation of Southern Dunlin should include increasing the connectivity between habitat patches.
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