White Geese Intermediate between Ross' Geese and Lesser Snow Geese

Abstract

THIS paper describes white geese with morphological characteristics between the Ross' Goose (Chen rossii) and the Lesser Snow Goose (Chen hyperborea hyperborea). Although the parentage of these white geese is unknown, they apparently represent the hybridization of Ross' Geese and Lesser Snow Geese in the wild. Johnsgard (1960) analyzed the occurrence of intratribal hybridization among Anserini based primarily on hybrids reported by Gray (1958). Ross' Goose is known to hybridize in captivity with both the Blue Goose (Chen caerulescens) and Lesser Snow Goose (Sibley, 1938; Gray, 1958: 53). Intergeneric hybrids have been reported from avicultural collections between the Ross' Goose and the domesticated Greylag Goose (Anser anser), Emperor Goose (Philacte canagicus), and Cackling Goose (Branta canadensis minima) by Sibley (1938), and the Red-breasted Goose (Branta rujicollis) by Scott (1951: 38). Sibley (1938) also documents the intertribal hybridization of a captive Ross' Goose and Blue-winged Goose (Cyanochen cyanopterus). Wild hybrids of Ross' Geese and these species have not been reported. Scientific nomenclature follows the A.O.U. Check-list (A.O.U., 1957), although taxonomic revisions of the Anatidae suggested by Delacour and Mayr (1945), Delacour (1954), and Johnsgard (1968) have been accepted by an increasing number of waterfowl biologists. Terminology and concepts of hybridization conform with the definitions and descriptions of Mayr (1963) and Short (1969). The term intermediate is used to denote the apparent hybrids of Ross' Geese and Lesser Snow Geese.