Breeding Habitat:Grassland
Nest Type:Cavity nesting
Migration Status:Short distance migrant
Nest Location:N/A
The Common Barn-Owl is a secretive species that is seldom observed during daylight hours away from its roosts. One of the least vocal owls, they are also difficult to detect at night except when they have large young in the nest. With its secretive behavior, this species is seldom recorded on BBS routes and the limited data is insufficient to establish trends for the breeding population. Barn-Owls are recorded in small numbers on CBCs, but these data may not be representative of the true winter status of this species (Stewart 1980). Hence, trends based on CBC data should be viewed with considerable caution.
Despite their widespread distribution in North America, recent data indicate substantial declines in Common Barn-Owl populations within portions of their range. These declines have been most apparent in the northeastern U.S. and some midwestern states (Colvin 1985, Martell 1991, Rosenburg 1992). Population trends in the southern and western states are less consistent and include local declines as well as range expansions (Marti and Marks 1989).
A number of factors have been identified as contributing to declines in barn-owl populations. Elimination of suitable foraging habitats may be the most important factor in the midwest, where many grasslands have been replaced by cultivated crops (Colvin 1985). Similar habitat loss has also occurred in the northeastern U.S., where the remaining stable populations are usually associated with extensive salt marshes (Rosenburg 1992). A shortage of suitable nest sites has been a limiting factor for some populations (Marti et al. 1979), although providing nest boxes has benefitted this species. Barn-owls are poorly adapted to cold weather, and declines along the northern portion of its range have been associated with severe winter weather (Marti and Wagner 1985). Additionally, pesticide contamination has been shown to adversely affect this species (Klaas et al. 1978, Mendenhall et al. 1983).
Colvin, B.A. 1985. Common Barn-Owl population declines in Ohio
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Klaas, E.E., S.N. Wiemeyer, H.M. Ohlendorf, and D.M. Swineford.
1978. Organochlorine residues, eggshell thickness and nest
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Marti, C.D., P.W. Wagner, and K.W. Denne. 1979. Nest boxes for the
management of barn owls. Wildl. Soc. Bull. 7:145-148.
Marti, C.D., and P.W. Wagner. 1985. Winter mortality in Common
Barn-Owls and its effect on population density and
reproduction. Condor 887:111-115.
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133 in B.G. Pendleton, ed. Proceedings of the western raptor
management symposium and workshop. Nat. Wildl. Fed. Scien.
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Mendenhall, V.M., E.E. Klaas, and M.A.R. McLane. 1983. Breeding
success of barn owls (Tyto alba) fed low levels of DDE and
dieldrin. Contam. Toxicol. 12:235-240.
Rosenburg, C. 1992. Barn owl, Tyto alba. Pp. 253-279 in K.J.
Schneider and D.M. Pence, eds. Migratory nongame birds of
managment concern in the Northeast. U.S. Fish and Wildl.
Serv., Newton Corner, MA.
Stewart, P.A. 1980. Population trends of barn owls in North
America. Am. Birds 34:698-700.