• McCollough, Mark A.
  University of Maine Graduate School
  

Photographs of 135 wintering bald eagles (Haliaeetus leucocephalus) of known age from Maine were examined to document plumage changes. Criteria were established to age 1/2-year (Juvenal plumage), 1 1/2-year (Basic I), 2 1/2-year (Basic II), and 3 1/2 year (Basic III) eagles primarily from head plumage and iris, beak, and cere color. Body plumage varied between individuals and was not a reliable aging characteristic. Definitive plumage was observed in some 4 1/2-year (Basic IV) and all 5 1/2-year (Basic V) eagles. However, individuals were observed with gray or brown flecking in the head plumage up to 8 1/2-years-of-age. Photographs of wintering eagles demonstrated that yearly body molt us not complete.

A winter feeding program for bald eagles was conducted in Maine during 1981-1985. Over 98,000 kg of carrion were distributed to feeding stations in 4 major eagle wintering areas. Numbers of individual eagles using the feeding stations increased from 66 in 1981-82 to 274 in 1984-85. Observations of 203 different banded eagles indicated that the wintering birds were primarily from Maine and the Canadian Maritime Provinces. First- and second eagles depended on the feeding stations for most of their winter diet, and older eagles used the feeding stations less frequently. Dispersal of first-year eagles probably decreased as a result of feeding. Average regional productivity did not increase but local production near feeding sites was enhanced. Energetics of feeding, feeding interactions with corvids, and management implications are also discussed.