# UKBirds

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## Slender-Billed Curlew

### Numenius tenuirostris

The Slender-billed Curlew, Numenius tenuirostris, is (or was) a bird in the wader family Scolopacidae. It breeds in marshes and peat bogs in the taiga of Siberia, and is migratory, formerly wintering in shallow freshwater habitats around the Mediterranean. This species has occurred as a vagrant in western Europe, the Canary Islands, the Azores, Oman, Canada and Japan.
The Slender-billed Curlew is a medium-sized curlew, 36-41 cm in length with a 77-88 cm wingspan. It is therefore about the same size as a Whimbrel, but it is more like the Eurasian Curlew in plumage. The breeding adult is mainly greyish brown above, with a whitish rump and lower back. The underparts are whitish, heavily streaked with dark brown. The flanks have round or heart-shaped spots. The non-breeding plumage is similar, but with fewer flank spots. Male and female are alike in plumage, but females are longer-billed than males, an adaptation in curlew species that avoids direct competition for food between the sexes. The juvenile plumage is very similar to the adult, but the flank are marked with brown streaking, the heart-shaped spots only appearing towards the end of the first winter.
Compared to the Eurasian Curlew, the Slender-billed Curlew is whiter on the breast, tail and underwing, and the bill is shorter, more slender, and slightly straighter at the base. The arrowhead-shaped flank spots of the Eurasian Curlew are also different from the round or heart-shaped spots of the Slender-billed. The head pattern, with a dark cap and whitish supercilium, recalls that of the Whimbrel, but that species also has a central crown stripe and a more clearly marked pattern overall; the pattern of the Slender-billed Curlew would be hard to make out in the field.
This species shows more white than other curlews, and the white underwings, along with the distinctive flank markings, are key identification criteria.
The call is a cour-lee, similar to that of the Eurasian Curlew but higher-pitched, more melodic and shorter. The alarm call is a fast cu-ee.