EXAMINATION OF OWL PELLETS FOR NORTHERN POCKET GOPHERS AT CRESCENT LAKE NATIONAL WILDLIFE REFUGE, NEBRASKA

Authors

Stacey L. Bonner, University of Nebraska at Kearney
Keith Geluso, University of Nebraska at KearneyFollow

Date of this Version

12-2010

Document Type

Article

Citation

The Prairie Naturalist· 42(3/4): December 2010, pp 138-141

Abstract

Analysis of regurgitated pellets from owls is a well-known and nondestructive method that provides useful information regarding diet (Errington 1930). This technique also is used to examine composition of small mammal communities and distribution of prey species (e.g. Kamler et al. 2003, Torre et al. 2004, Poole and Matlack 2007). In western Nebraska, two species of owls that regularly breed in the region are the common barn owl (Tyto alba) and great horned owl (Bubo virginianus). In the early 1970s, Rickart (1972) studied the diet of both species at Crescent Lake National Wildlife Refuge (CLNWR), Garden County, Nebraska. Rickart (1972) recovered 447 prey items representing 14 taxa of small mammals from regurgitated pellets, including remains of 3 northern pocket gophers (Thomomys talpoides) from pellets of great horned owls. Those findings extended the range of T. talpoides about 60 km northeast from Cheyenne County into the Sandhill Region of Nebraska, a region and soil type where T. talpoides previously has not been documented in the state (Jones 1964). Prior to our study, we attempted to locate voucher material of mammals from Rickart (1972) without success (E. Rickart, Utah Museum of Natural History and R. Timm, University of Kansas, Natural History Museum; pers. comm.). Thus, we initiated our study to determine whether tangible evidence (e.g., a voucher specimen) could be obtained for the presence of T. talpoides at the refuge, which may represent an isolated population in need of conservation. We also compared the diet of owls from the refuge in the early 1970s (Rickart 1972) to diets based on recent collections of owl pellets (this study).