ABSTRACT
This chapter identifies the concentrations of Selenium (Se) in avian diets and in avian eggs and other tissues that are toxic, and discusses how different chemical forms of Se and their interactions with other environmental contaminants can alter toxicity. Se toxicosis effects in several species of aquatic birds found at Kesterson Reservoir in 1984-1986 were described previously. Se concentrations in wild-trapped birds can be measured in blood as a nonlethal approach for assessing exposure and, when combined with laboratory findings, can be interpreted as to whether exposures are potentially harmful. Analyses of feathers may provide useful information concerning exposures of birds to Se if they are considered carefully. Based on the information available, the chapter concludes that Se concentrations in blood can indicate recent dietary exposures of birds, but relationships vary among species, and concentrations in blood can not be clearly related to effects on reproduction or individual health and fitness.
