Nest-Robbing by Cooper's Hawks

Songbird Populations in Fluctuating Environments: Predator Responses to Pulsed Resources

“…That these observations were made only at Wood Thrush nests (with one exception) likely reflects the higher vulnerability of this species. Wood Thrushes build fairly large nests that are often conspicuously placed in shrubs, and it is not uncommon for raptors to raid active nests for chicks (Nelson 1968, Rosenfield and Bielefeldt 1993, McCallum and Hannon 2001K. A. Schmidt, personal observation).…”

Raptor Predation of Northern Bobwhite Nests

“…Certainly, avian nest predation by raptors is not novel. Both Great Horned Owls (Schaub et al 1992) and Cooper's Hawks (Hamerstrom and Hamerstrom 1951, Meng 1959, Nelson 1968, Loiselle and Hoppes 1983 have been reported to depredate nests of altricial species. Moreover, other Strigiformes (Custer 1973, Levin et al 1977, Landin 1978, Schaub et al 1992, Thompson et al 1999 and Falconiformes (Freer 1973) have been documented as nest predators of altricial birds.…”

“…In the case of altricial species, young are hatched helpless, naked, and blind, and subsequently reared in the nest for 2-3 wk; thus, begging for food by chicks and adult tending activities render them more detectable to predators, including raptors. Consequently, raptors have often been assumed to remove chicks out of the nest one by one until all chicks are taken (e.g., Custer 1973, Nelson 1968, Schaub et al 1992. However, observations for many of these reported occurrences were limited to diagnostic field sign from pellet counts, nest-site searches, plucking/roosting perches, and observational data (Nelson 1968, Custer 1973, Freer 1973, Levin et al 1977, Landin 1978; hence, the occurrence of such nest predations of altricial species is likely underestimated.…”

“…Consequently, raptors have often been assumed to remove chicks out of the nest one by one until all chicks are taken (e.g., Custer 1973, Nelson 1968, Schaub et al 1992. However, observations for many of these reported occurrences were limited to diagnostic field sign from pellet counts, nest-site searches, plucking/roosting perches, and observational data (Nelson 1968, Custer 1973, Freer 1973, Levin et al 1977, Landin 1978; hence, the occurrence of such nest predations of altricial species is likely underestimated. More recent studies have shown higher rates of nest mortality of altricial birds caused by raptors using video camera sampling (Schaub et al 1992, Thompson et al 1999.…”

The accipiters : goshawk, cooper's hawk, sharp-shinned hawk /

“…The taste for young and helpless birds often leads accipiters into nest robbing. Nelson (1968) watched a Cooper's hawk in British Columbia capture a nestling robin directly out of the nest. Meng (1959) observed a Cooper's hawk bring 2 live scarlet tanager nestlings to its nest for the young Cooper's hawks.…”