Bird of the Week

This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the Williamson’s sapsucker. Among most of the species of woodpeckers that we see here, plumage differences between the sexes are limited to markings on the face and head. Such is not the case with the Williamson’s sapsucker. Males and females are so different in appearance that until they were seen together at a nest, they were identified as separate species and given different names. Males have glossy black upperparts, two white stripes on the face, a white patch on the wing and a red throat patch. The more camouflaged female has horizontal black and white barring on the back, a black breast patch and brown head. Vivid yellow coloring on the belly is a marking shared by both sexes. Williamson’s sapsuckers drill neat rows of tiny holes. known as wells, in conifers. Here they feed on tree sap, insects attracted to it and inner tree tissues. In spring, shallow holes tap into the xylem layer, which carries water from the roots to the leaves. Later in the season, larger rectangular wells tap into the phloem layer transporting food from the leaves to other parts of the tree. As old wells dry up, new ones are formed in a ladder formation up the tree. When their young are in the nest, they eat and feed to their chicks primarily ants, which they pick from tree trunks and branches. They also eat beetles, aphids, flies and other insects, Later in the season they add fruits and berries. These large sapsuckers breed in higher-elevation dry forests in North America west of the Rocky Mountain range. Their specific habitat requirements, including large, mature conifers, have made them an indicator species of old-growth forest health. Some northern populations migrate as far as southern Mexico for the winter while others just move downslope. They are never reported here in high numbers and only rarely in winter months. Although global population numbers of Williamson’s sapsuckers are considered stable, in Canada, where suitable habitat has been lost to commercial logging, they have remained on the Endangered Species list since 2005. For information on events, visit www.weminucheaudubon.org and www.facebook.com/weminucheaudubon/.