SHORT COMMUNICATIONS 
185 
the nighthawk in Montana would not overlap in 
range with a Chuck-will’s-widow at any time of 
year. Mobbing of a nighthawk, potoo, or any other 
strictly insectivorous caprimulgiform in either 
scenario would be a case of mistaken identity. 
The scarcity of published observations of capri- 
mulgiforms being mobbed suggests the behavior 
is uncommon. The topic is worthy of attention 
because it could reveal new information on 
mobbing behavior, predator recognition, and 
interactions among caprimulgiforms and other 
birds. 
ACKNOWLEDGMENTS 
We thank R. M. Brigham, C. E. Braun, Paul Hendricks, 
M. T. Nolen, and T. A. Sordahl for valuable comments on 
the manuscript. 
LITERATURE CITED 
Altmann, S. A. 1956. Avian mobbing behavior and 
predator recognition. Condor 58:241-253. 
Castro-Siqueira, L. de. 2010. Observation of mobbing 
towards a Common Potoo ( Nyctibius griseus). Boletm 
SAO 20:1-4. 
Cleere, N. 1998. Nightjars: a guide to the nightjars, 
nighthawks, and their relatives. Yale University Press, 
New Haven, Connecticut, USA. 
Cleere, N. 1999. Family Caprimulgidae (nightjars). Pages 
302-331 in Handbook of the birds of the world. 
Volume 5. Barn-owls to hummingbirds (J. del Hoyo, 
A. Elliott, and J. Sargatal, Editors). Lynx Edicions, 
Barcelona, Spain. 
Cleere, N. 2010. Nightjars, potoos, frogmouths, Oilbird, 
and owlet-nightjars of the world. Princeton University 
Press, Princeton, New Jersey, USA. 
Ficken, R. W., M. S. Ficken, and E. S. Hadaway. 1967. 
Mobbing of a Chuck-will’s-widow by small passer¬ 
ines. Auk 84:266—267. 
Gehlbach, F. R. and J. S. Leverett. 1995. Mobbing of 
Eastern Screech-Owls: predatory cues, risk to mobbers 
and degree of threat. Condor 97:831-834. 
Kent, T. H. 1999. Common Nighthawk draws a crowd. 
Iowa Bird Life 69:107. 
Marks, J. S., R. J. Cannings, and H. Mikkola. 1999. 
Family Strigidae (typical owls). Pages 76-151 in 
Handbook of the birds of the world. Volume 5. Barn- 
owls to hummingbirds (J. del Hoyo, A. Elliott, and J. 
Sargatal, Editors). Lynx Edicions, Barcelona, Spain. 
Owre, O. T. 1967. Predation by the Chuck-will’s-widow 
upon migrating warblers. Wilson Bulletin 79:342. 
Pickwell, G. and E. Smith. 1938. The Texas Nighthawk 
in its summer home. Condor 40:193-215. 
Poulin, R. G., S. D. Grindal, and R. M. Brigham. 1996. 
Common Nighthawk ( Chordeiles minor). The birds of 
North America. Number 213. 
Thayer, G. H. 1899. The Chuck-will’s-widow on ship¬ 
board. Auk 16:273-276. 
The Wilson Journal of Ornithology 123(1): 185-187, 2011 
Observation of Ground Roosting by American Crows 
Cory M. Shoemaker 12 and Richard S. Phillips 13 
ABSTRACT.—Communal winter roosts of Ameri¬ 
can Crows ( Corvus brachyrhynchos) often occur in 
urban areas and may number in the thousands of 
individuals. We documented the distribution of urban 
roosts of American Crows in central Ohio and, on 12 
January 2010, we observed a roost of —2,500 
individuals with —250-300 birds roosting on the 
ground. The ground roosting birds remained stationary 
for the entire observation period of —45 min indicating 
this location was not a stopover site. This behavior may 
increase thermoregulatory benefits during cold nights 
assuming decreased predation threats in urban environ- 
1 Department of Biology, Wittenberg University, Spring- 
field, OH 45501, USA. 
2 Current address: 235 Barbara Deer Kuss Science 
Center, Department of Biology, Wittenberg University, 
Springfield, OH 45501, USA. 
3 Corresponding author; e-mail: rphillips@wittenberg.edu 
ments. We suggest urban ground roosting behavior by 
crows may be adaptive in colder environments. 
Received 16 February 2010. Accepted 11 November 
2010 . 
Communal roosts of nonbreeding birds have 
been the subject of study across taxa. Possible 
factors driving communal roosting are threefold: 
protection from predation, informational purposes 
such as relaying food locations, and potential 
thermal benefits (Beauchamp 1999). Communal 
winter roosts of corvids have been documented 
for several species (Everding and Jones 2006, 
Zmihorski et al. 2010). The increasing occurrence 
of corvid roosts in human-dominated landscapes 
and the potential impact of disease transmission 
