Diet and Nesting Success of Barn Owls Breeding in Western Nebraska

Abstract

-We analyzed the diet of barn owls (Tyto alba) in Lincoln County, Nebraska during nesting seasons of 1984 through 1986 and their nest success in 1985 and 1986. Nesting attempts were made at 9 of 13 nest sites checked in 1985 and at 12 of 15 nest sites in 1986. Microtus ochrogaster comprised 32.7% of 10,140 prey items overall with marked increase in percent from 1985 to 1986. Barn own reproduction increased from 1985 to 1986 with more nests initiated, a higher proportion of successful nests and higher mean number of young fledged per nest attempt. Proportions of prey in the diet were significantly different from proportions of prey captured by trapping. Microtus ochrogaster was overrepresented and Peromyscus maniculatus underrepresented in the diet. Annual percentages of M. ochrogaster and Perognathus hispidus in the diet were negatively correlated with Reithrodontomys megalotis and with P. maniculatus but were not correlated with each other. Reithrodontomys megalotis and P. maniculatus were not correlated with each other. Reithrodontomys megalotis decreased and P. hispidus increased in the diet each year. A number of factors influence barn owl reproductive success including diet, quality of nest site and foraging ability of