POSSIBLE EFFECTS OF PCB CONTAMINATION ON FEMALE PLUMAGE COLOR AND REPRODUCTIVE SUCCESS IN HUDSON RIVER TREE SWALLOWS

Abstract

Abstract Chemical contaminants in the environment can influence both morphological and behavioral traits. Ornamental traits such as plumage color may be especially valuable in detecting the effects of toxic chemicals in the environment, although they have been little used to date. We examined patterns of plumage color in subadult female Tree Swallows (Tachycineta bicolor) breeding in an area on the Hudson River that had high levels of PCB contamination and compared them with specimens from other parts of the species' range and with data from two previous studies of plumage color. Tree Swallows are one of the few species of birds where females, but not males, have a distinctive subadult plumage during their first breeding season. Females from four breeding colonies in contaminated areas had significantly more adult-type blue-green coloring than females from the rest of the species' range. Subadult female plumage color at these sites formed a continuum between the normal dull brown plumage found elsewhere a...