Publication Date



Intro and Objectives: Bald Eagle (Haliaeetus leucocephalus) populations across the lower 48 states have rebounded from 417 breeding pairs in 1963 (Sprunt 1963) to an estimated 5,478 in 1998 (Millar 1999). The Chesapeake Bay population grew exponentially from 73 pairs in 1977 to 601 pairs in 2001 (Watts et al. 2008). The population has continued to grow and now is estimated at over 1,000 breeding pairs (Maryland Department of Natural Resources 2004, Watts and Byrd 2008). The recovery of eagle populations throughout most of their range prompted the US Fish and Wildlife Service (USFWS) to remove the species from the Endangered Species List in 2007 (USFWS 2007, Watts and Byrd 2008). Eagles remain protected under the federal Bald and Golden Eagle Protection Act, Migratory Bird Treaty Act, and Lacey Act (Millar 1999). Although breeding populations have recovered, many threats continue to affect breeding and non‐breeding eagles. Current threats include electrocutions, line strikes, disease, contaminants, habitat loss, and vehicle collisions (Millar 1999, Millsap et al. 2004). Concern over Bald Eagle deaths related to the electrical infrastructure at the US Army’s Aberdeen Proving Ground (APG) prompted a Biological Assessment (BA) of the species under the Endangered Species Act in 2004. As a result of recommendations in the BA, the Army contracted with The Center for Conservation Biology at the College of William and Mary to study the mortality problems at APG. APG manufactures, stores, and tests chemicals during military programs. Improper disposal of these chemicals in the past has led to the presence of contaminants in the soil and water on base. APG is actively cleaning up contaminated sites through the federal Superfund program but many contaminants continue to persist in the environment. Bioaccumulation of contaminants in Bald Eagles can reduce productivity and hatching rates and cause death by poisoning (Henny & Elliott 2007). In spring 2008, CCB biologists conducted a preliminary study of contaminants in APG eagles while visiting eagle nests on base. Objectives: 1) To determine mercury, pesticide, and PCB contaminant levels in nestling eagles, and 2) To determine contaminant levels in adult females by testing levels in non‐viable eggs.


Bald Eagle


Center for Conservation Biology Technical Report Series. College of William and Mary, Williamsburg, VA.