Jl. Kramer et Pt. Redig, 16 YEARS OF LEAD-POISONING IN EAGLES, 1980-95 - AN EPIZOOTIOLOGIC VIEW, The Journal of raptor research, 31(4), 1997, pp. 327-332
A 16-yr (1980-95) retrospective study was conducted to assess differen
ces in the prevalence of lead poisoning in Bald (Haliaeetus leucocepha
lus) and Golden (Aquila chrysaetos) Eagles admitted to The Raptor Cent
er at the University of Minnesota. These years encompass the period be
fore and after federal legislation was enacted restricting the use of
lead shot for hunting waterfowl on federal lands (1991). Of 654 eagle
admissions reviewed, 138 cases of lead-poisoned eagles were evaluated
for the following: recovery location, blood lead concentration, month
of admission, radiographic evidence of lead in the ventriculus and pri
mary cause of admission. The prevalence of lead poisoning in eagles di
d not change after 1991, but mean blood concentrations of lead in the
same population decreased. These findings call into question current t
heories regarding the sources of lead for eagles and the actual mechan
isms by which eagles are poisoned. Lead poisoning is a continuing prob
lem both regionally and internationally, and many variables related to
this toxicity have yet to be conclusively defined.