BALD EAGLE (HALIAEETUS LEUCOCEPHALUS) POPULATION PRODUCTIVITY AND DENSITY DEPENDENT EFFECTS IN MICHGAN, 1961-2010

Abstract

The bald eagle (Haliaeetus leucocephalus) population in Michigan has undergone a significant recovery following the ban of the pesticide dichlorodiphenyltrichloroethane (DDT), and its subsequent derivatives, mainly dichlorodiphenyl-dichloroethylene (p,p'-DDE). This recovery however, has not been uniform throughout the state. Michigan is a heterogeneous habitat, causing the best-fit, experienced breeding pairs to settle in high quality breeding areas first. This high quality habitat mainly occurs in the inland regions of Michigan. These areas experienced the greatest productivity until the 1990's, quickly recovering from the detrimental effects of DDT. Great Lakes breeding areas, particularly Lake Michigan and Lake Huron, are now more productive than inland breeding areas. These Great Lakes breeding pairs however, are the least efficient breeders with greater amounts of changeover between nesting pairs within one breeding area in comparison to inland pairs. A constant turnover of breeding pairs may overshadow any underlying effects causing decreased reproductive fitness in Great Lakes adults.