<i>Protocalliphora</i> (Diptera: Calliphoridae) Infestations of Nestling Red-shouldered Hawks in Southern Ohio

We examined nestling Red-shouldered Hawks (Buteo lineatus) in 56 nests (147 nestlings) in suburban southwestern Ohio and in 25 nests (67 nestlings) in rural forested Hocking Hills in south-central Ohio, ∼180 km east of southwestern Ohio. Fifteen of 25 nests in Hocking Hills had Protocalliphora avium larvae on one or more nestlings and/or pupae in the nest material. Nineteen nestlings had larvae in one or both ears, an additional 14 had evidence of larvae outside the ears, 32 were not visibly parasitized, and two were not examined or their status was not reported; in contrast, no nests and no nestlings were parasitized in southwestern Ohio. Reproductive rate (young fledged/nest) did not differ between southwestern Ohio and Hocking Hills (2.4 ± 0.1 young/nest at southwestern Ohio vs. 2.7 ± 0.2 at Hocking Hills; P = 0.214). Parasitized nests at Hocking Hills were no more likely to have been used in the previous breeding season than non-parasitized nests (χ2 = 0.903, P = 0.342, n = 22). Similarly, number of young fledged/nest at parasitized nests did not differ from that at non-parasitized nests within Hocking Hills (U = 75.0, P = 1.00, n = 25; mean (± SE) number of young = 2.7 ± 0.3 vs. 2.7 ± 0.3 at parasitized and non-parasitized nests, respectively). The Protocalliphora loads we observed did not appear to have a negative effect on the fledging rate of nestling Red-shouldered Hawks; however, we did not assess any other potential effects of parasitism.