Prevalence of Aspergillus fumigatus in free-living goshawks (Accipiter gentilis atricapillus).

During the fall migration of 1972 and 1973 unusually large numbers of goshawks (Accipiter gentilis atricapillus) were counted at Hawk Ridge in Duluth, Minnesota. These birds were sampled for prevalence of fungi of the genus Aspergillus. Fungi of this genus were recovered from 26 of 49 birds (53%) in 1972 and 4 of 45 (7%) birds in 1973. Aspergillosis was confirmed at necropsy in three wild goshawks in 1972, but none in 1973. The disease was further confirmed at necropsy in 8 of 12 (67%) goshawks trapped in the fall and retained for falconry in 1972 and in 2 of 17 (12%) such birds in 1973. We suggest that the stress of intraspecific agonistic behavior in conjunction with a high density of goshawks and greatly reduced prey base may increase the susceptibility of these hawks to aspergillosis.