Monday, 10 September 2007

Three-toed Woodpecker: adult male ID

The most easily observed difference between sexes of this species is the yellow colouration of the male’s central and fore-crown. This can vary in extent and tone, sometimes being quite bright lemon, sometimes mustard, and often flecked with black. Some white feather bases may also push through. The forehead is black, specked with white. Black areas bordering the yellow crown are usually glossy. Males also have longer black and white nasal tufts than females, but this feature only really visible in the hand. In addition, males are larger and heavier and have longer wings, tarsus and culmen. Of these, perhaps only bill length is discernible in the field. The greater lengths for tarsus and especially bill for males over females and relatively shorter tail in males in relation to bill and leg length are related to foraging niche and feeding techniques. Photo left: Adult male tridactylus race, Finland (Jari Peltomaki). Note the unbarred white back and snowy white underparts.

No comments: