Wallcreeper

The wallcreeper is 15.5–17 centimetres (6.1–6.7 in) long, with a weight of 17–19 grams (0.60–0.67 oz). Its plumage is primarily blue-grey, with darker flight and tail feathers. In summer, the males have a black throat grading into the grey of the rest of the body, and females can have either a white throat or a small dark patch on the throat; in autumn and winter, both sexes have a white throat. Its most striking plumage feature, though, are its extraordinary crimson wings with white spots. Voice: Though largely silent, both male and female wallcreepers sing, the females generally only while defending feeding territories in the winter. The song is a high-pitched, drawn-out whistle, with notes that alternately rise and fall. During the breeding season, the male sings while perched or climbing.