Peregrines and Pesticides in Alaska

Cade, Tom; White, Clayton; Haugh, John

The Peregrine is one of the 50 species of rare and endangered birds currently listed in the 'Red Book' of the U.S. Fish and Wildlife Service (Resource Publication 34, July 1966). It has experienced unprecedented reductions in breeding populations on two continents since World War II, and its continued existence in North America appears to be threatened to a greater extent than the more widely publicized case of the Bald Eagle (Haliaeetus leucocephalus). While we are much encouraged to be able to report that this Yukon population of Peregrines is still intact and reproducing at a normal rate, the widespread occurrence of pesticide residues at rather high levels in the eggs and tissues of these falcons allows us no sanguine feeling about their future. The sorry spectacle of what has happened to the Peregrines in Finland belies the easy notion that arctic and boreal populations are specially protected by the wilderness nature of their environment. These same falcons winter in regions grossly affected by human habitation. If other associative evidence is a valid criterion-and we think it is-then these Alaskan falcons may be perilously balanced near the threshold level of organochlorine residues that initiates dysgenic reproductive behavior and eventual population decline. The Alaskan and Canadian falcons constitute the last substantial breeding populations of this species in North America, and as their fate may well depend on how these residues continue to accumulate, these northern Peregrines certainly should be watched closely over the next few years for evidence of reproductive malfunction coincident with continued, or increasingly, high levels of chlorinated hydrocarbons in their tissues.

Peregrines and Pesticides in Alaska

Series