Low productivity of bald eagles on Prince of Wales Island, southeast Alaska

Investigated reproductive success of Bald Eagles (Haliaeetus leucocephalus) on Prince of Wales Island, Alaska from 1991-93. Productivity (0.13 young p roduced per occupied territory) was the lowest recorded for the species thr oughout its geographic range. Productivity was not significantly different among different habitats including remote roadless areas vs. roaded and log ged areas, which suggested that habitat alterations were not the cause of l ow productivity. Because nesting densities were high and I observed some ef fects of proximity of nearest neighbor pairs, I suggest these densities (pr oximate factor) were affecting productivity through reduced food availabili ty (ultimate factor). However, I could not rule out the effects of environm ental contaminants, although this seemed unlikely because of the distance o f the island from industrial and agricultural areas. I discuss the various potential causes of this low rate of productivity.