Nesting Ecology of Raptor Species On the Noatak River, Alaska

Smith, Dwight; Zak Ball, J.A; Ellis, David; Johnson, Brad; Ellis, Catherine

The extensive wilderness of the Noatak National Preserve in arctic Alaska supports a rich flora and fauna, including small but significant nesting populations of the threatened arctic peregrine falcon (Falco peregrinus tundrius) and other species of raptors. Surveys of nesting raptors along the Noatak River conducted in 1987 and 1988 were compared with earlier surveys to establish a baseline for future studies of raptor populations. Observations of human activities and disturbance factors related to nesting raptors were recorded in 1988. Ten species of raptors were recorded during the Noatak surveys, including nesting populations of the arctic peregrine faclon, gyrafalcon (Falco rusticolus), merlin (Falco columbarius) golden eagle (Aguila chrysaetos) and rough-legged hawk (Buteo lagopus). Other common raptor species included the northern harrier (Circus cyaneus) and short-eared owl (Asio flammeaus) which nested in tundra habitats adjacent to the river. Presence of the peregrine falcon nesting population suggests recolonization of the Noatak watershed by this species after an apparent absence during most of the last decade. Observations on raptor species populations, distribution, nest site selection, nesting chronology, productivity and flood habits are presented. Including raptors, 49 species of birds were observed during the survey, most commonly shorebirds and waterfowl. The highest variety of birds was found in association with riverine habitats, although nonriverine habitats were not surveyed as extensively. Evidence of human activities, although infrequent, increased downstream along the Noatak River. Human activities observed were aircraft flights, boating, fishing and camping. Some evidence of human activity was also noted at several raptor eyries. Raptor eyries along the Noatak River are inherently vulnerable to human activity. This suggests that adequate precautionary measures be taken to protect nests and young of threatened or endangered species and other nesting raptors.