Invertebrate populations in the nests of a screech owl (Otus asio) and an American kestrel (Falco sparverius) in central New York

Screech owl (O. asio) nest material from a tree hole in Syracuse, New York State, contained 22 991 arthropods of 61 species. Arthropod density was 131/g dry weight of nest material. An American kestrel (F. sparverius) nest in a nest box in Jamesville, New York, yielded 26 553 invertebrates of 93 species. Arthropod density was 38/g dry weight of nest material. Lists of the species found and their populations are presented, and their trophic and symbiotic relationships are discussed. Bird parasite levels were extremely low. The litter fauna was dominant in the screech owl nest (in which the most abundant arthropods were Ramusella clavipectinata, Acotyledon paradoxa, Tydeus sp., Tarsonemus sp. and Neoxenoryctes reticulatus), while the stored products fauna was dominant in the kestrel nest (in which the most abundant species were Lardoglyphus falconidus, Cheyletus trouessarti, Leptometopa latipes, Tarsonemus sp. and Lepidoglyphus fustifer).