Physical characteristics

Most male sunbirds and many of the females are brightly colored, with iridescent plumage covering varying proportions of their bodies. The color of the iridescence changes with the angle of incident light such that a blue may suddenly appear green or black. Many have marked contrasts in their colors, especially the double-collared group amongst the genus Cinnyris, who have broad red bands across their chests. Brightly colored pectoral tufts, usually yellow or red, are a feature of many species, particularly among males that use them in courtship and aggressive displays. The predominantly black bills of sunbirds are nearly all decurved, but the extent of the curvature varies from very slight in the genus Deleor-nis to the sickle-shaped bill of the golden-winged sunbird (Drepanorhynchus reichenowi). The birds' tongues are long and may be extruded far beyond the tip of the bill. The tongues vary in size and shape, with tubular structures and serrations

Female malachite sunbird (Nectarinia famosa) in its nest. (Photo by Kenneth W. Fink. Bruce Coleman Inc. Reproduced by permission.)

at the tips being most common. Tails may be short and square-ended, or graduated and elongated, with males of the genus Nectarinia, Drepanorhynchus and Aethopyga having extended central tail feathers. No sunbirds have truly forked tails, even the fork-tailed sunbird (Aethopyga christinae) gets its name from central tail feathers that are elongated into a forked shape. The legs are long and thin and usually black, with feet having curved claws.

The smallest sunbird is the crimson-backed sunbird (Lep-tocoma minima), which may be only 3.5 in (9 cm) long and weigh as little as 0.14 oz (4 g). The largest sunbird is the Sâo Tomé sunbird (Dreptes thomensis), males of which may be 9 in (23 cm) long and weigh 0.9 oz (26 g). The 10 species of spiderhunters in the genus Arachnothera are larger than almost all of the other sunbirds and are restricted to Asia. Their sexes are similar and lack any iridescent plumage. Their de-curved bills are very long, being at least twice the lengths of their heads.

0 0

Post a comment