Short Communications 
The Wilson Journal of Ornithology 124(4):783~787. 2012 
Protocalliphora (Diptera: Calliphoridae) Infestations of Nestling 
Red-shouldered Hawks in Southern Ohio 
Cheryl R. Dykstra , 15 Jeffrey L. Hays , 2 Melinda M. Simon , 3 and Ann R. Wegman 4 
ABSTRACT.—We examined nestling Red-shoul¬ 
dered Hawks {Buteo lineutus ) 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 Protocalli¬ 
phora avium larvae on one or mote 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 iwo were not examined or their status was not 
reported; in contrast, no nests and no nestlings were 
parasitized in southwestern Ohio. Reproductive rate 
(voting fledged/nest) did not differ between southwest¬ 
ern Ohio and Hocking Hills <2.4 t 0 I 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 ihe prev ions breeding season 
than non-parasitized nests (x = 0.903. I' 0.342. n 
22). Similarly, number o! young fledged/nest at 
parasitized nests did not differ from that at non- 
parasitized nests within Hocking Hills (V 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. Received 29 I'chntarv 2012. Accepted 29 
May 2012. 
Many raptor species are infested by one or more 
species of ectoparasitic Protocalliphora Hies (Dip¬ 
tera: Calliphoridae), commonly called bird blow 
flies (Sabrosky et al. 1989. Bennett and Whitworth 
1992). Adults of these Diptera lay their eggs on 
nestlings, typically when the nestlings are young 
(Tirell 1978, Sabrosky et al. 1989). The fly eggs 
hatch within 24-48 hrs and larval Protocalliphora 
Raptor Environmental. 7280 Susan Springs Drive, West 
Chester. OH 45069, USA. 
RAPTOR Inc.. 1419 Holmanview . Wyoming. OH 45215, 
USA. 
9016 Winthrop, Cincinnati. OH 45249, USA. 
‘Cincinnati Museum of Natural History. 1301 Western 
Avenue, Cincinnati, OH 45203, USA. 
Corresponding author; e-mail: cheryldykstra@juno.com 
feed on nestling blood until they mature, when they 
drop from the nestlings into the nest material and 
pupate (Sabrosky et al. 1989). The larvae are 
typically found in nestling ear canals, nares. 
axillary area, and feather sheaths in raptors (Tirrell 
1978. Sabrosky et al. 1989, Philips 2007) and also 
in the nesting material (Sabrosky et al. 1989). 
The effect of Protocalliphora on raptor nestling 
health and survival differs among species and 
studies. Researchers hav e blamed Protocalliphora 
for impaired development, weakness, and death in 
some eases (Philips 2007): heavily infested Red¬ 
tailed Hawk (Buteo jamaicensis) nestlings in 
North Dakota were smaller and weaker than their 
siblings and died as a result of siblicide; one of 
these nestlings had 213 larvae in multiple 
locations (Tirrell 1978). Protocalliphora likely 
caused the death of 26 nestling Prairie Falcons 
(Falco mexiemus) in nine eyries in Utah (White 
1963). In contrast, Protocalliphora infestations 
apparently hud little effect on nestling Red¬ 
shouldered Hawks {B. Uneatus) in Wisconsin (King 
et til. 2010). Broad-winged Hawks {11 platypterus) 
in New York (Crocoll and Parker 1981). Red¬ 
tailed. Red-shouldered, and Cooper's hawks (Ac- 
cipher cooperii) in New York (Sargent 1938), and 
Red-tailed Hawks in Montana (Scidensticker and 
Reynolds 1971). Typical infestations likely pro¬ 
duce only minor or no negative effects (Sabrosky 
et al. 1989). 
Protocalliphora avium occurs in northern and 
northeastern North America and has been docu¬ 
mented in at least 12 species (Sabrosky et al. 
1989). P. avium is replaced in western North 
America by the closely related P. asiovora 
(Sabrosky et al. 1989. Bennett and Whitworth 
1992). However, the distribution of P. avium is 
not well documented, and its presence and 
prevalence on raptor nestlings has been typically, 
although not exclusively, reported anecdotally 
(Sargent 1938. White 1963, Seidenstickcr and 
Reynolds 1971. Bohm 1978). 
Our objective was to investigate the presence 
and prevalence of Protocalliphora ectoparasites 
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