EXPERIMENTAL DISPERSAL OF WINTERING SNOW AND ROSS' GEESE

Abstract

Wintering white geese in New Mexico historically have been concentrated on the Bosque del Apache National Wildlife Refuge (NWR). Numbers of wintering lesser snow geese (Chen caerulescens caerulescens) and Ross' geese (Chen rossii) on the refuge tripled from 1976 to 1985, reaching a peak of 56,800 birds. By 1985, geese extended their range northward to include the entire middle Rio Grande Valley from Albuquerque south to the refuge (Bosque del Apache NWR surveys; N.M. Dep. Game and Fish, unpubl. data; Fig. 1). Concurrently, goose depredation on crops increased throughout the middle Rio Grande Valley, and most foods planted on the refuge for sandhill cranes (Grus canadensis) and wintering waterfowl were consumed by geese. Incidences of fowl cholera and avian tuberculosis also increased (Bosque del Apache NWR, unpubl. data). These conditions were unacceptable under the management planning goals for the Rocky Mountain greater sandhill cranes (G. c. tabida) and the cross-fostered flock of endangered whooping cranes (Grus americana) that also spend the winter in the middle Rio Grande Valley. Because hunting and associated activities were unable to reverse the growth of the snow goose-Ross' goose (white goose) populations to meet the management objective of 20,000 geese for the refuge, actions were implemented to force a portion of the early-arriving geese south before roosting and feeding patterns became established in early autumn. Our objectives were to document movements of geese in response to these actions, and assess the effect of the program on sandhill and whooping cranes. STUDY AREA