Format: Adobe Acrobat File (PDF),  19pp Publisher: AVVAR Books (May 2005) Abstract

The geese wintering on the lower Colorado River at the Cibola National Wildlife Refuge (CNWR) originate mainly from northwestern and southwestern Wyoming (50-%), Utah (30%), and southern Alberta (10%) These birds differ morphologically and descriptions are given. In addition 8 additional taxa of white-cheeked geese found at CNWR are briefly described and discussed. The number of wintering geese at CNWR has been declining for a decade. Determination of population demographics show that this decrease in numbers is characterized by reduced proportions of breeding pairs, young per pair that did breed, and immatures in the population. Reduction in overall numbers may be affected by geese wintering further north or shifting wintering grounds, poor reproduction due to drought conditions on the breeding grounds, and/or by impacts from early season hunting. Management implications are discussed.

Key words: Branta canadensis, Branta hutchinsi, geographic variation, demographics, family group counts, management