Ecological Aspects of the Blue-Snow Goose Complex

Abstract

T}tE taxonomic relationship of the Blue Goose (Chen caerulesceus cacrulescens) and the Lesser Snow' Goose (Chcn hyperborca hyperborea) has long created controversy among avian systematists, e.g., Blaauw (1908), Soper (1930), Sutton (1932), Manning (1942), and Manning et aI. (1956). I believe that the two forms are conspecific and that the species consists of two subspecies: a large form, Chcn cacruIcscens atIantica, which has no color phases, and a smaller form, Chcn caerulescens caeruIescens, which is polymorphic and has two clearly defined color phases. The remainder of the discussion is concerned only with the latter race. Because of slight pleiotropic differences between the phases, reflected especially in nesting and incubation behavior, some may prefer to follow the lead of Manning et al. (1956) and confer subspecific status on hyperborea. However, my opinion is that such differences should be considered as dichromatic polymorphs of a single subspecies Chc•t c. caeruIesce•s. 76 Cooc}•, The Blue-Snow Goose Complex .auk Vol. 78 3O • Goose 77 Auk I Coocn, The I htc-3'•]ozo Complex Vol. 78 ] Auk VoL 78] CoocH, The Blue-Snow Goose Complex Auk ] CoocIt, The Blue-Snow Goose Complex 89 Vol. 78 J

A comparative study of egg mass and clutch size in the Anseriformes

“…Furthermore, if parental care were so costly, brood amalgamation would not be so common in waterfowl (Afton and Paulus 1992;Beauchamp 1997). Nevertheless, some studies of waterfowl have found that predation risk (Hilden 1964;Cooch 1961;Lessells 1986) or parental vigilance (Forslund 1993) increased with brood size.…”

The evolution, maintenance and adaptive function of genetic colour polymorphism in birds

“…In the bridled guillemot, the bridled form significantly increased in frequency from 3.5% in 1946 to 5.9% in 2000, and between 1982 and 1999 bridled individuals were more successful at raising chicks than individuals of the non-bridled morph (Harris, Rothery & Wanless, 2003). In the snow goose, the blue morph increased in frequency between 1929 and 1977 (Cooch, 1963), and blue females were more productive (Cooch, 1961). These two studies show that one morph can be locally favoured leading to an increase in its frequency.…”

“…One needs to determine changes in gene frequencies over time, colour-dependent emigration and immigration rates (e.g. Cooch, 1961 ;Cooke, MacInnes & Prevett, 1975), survival rate, reproductive success and mate choice rules of different colour types. Because different colour morphs may be adapted to specific ecological factors, studies should be carried out in several populations to ascertain the general applicability of results found in one population, since the balance between benefits and costs of displaying a given coloration may vary from one location to another.…”

Environmental Influence on Life‐History Traits: Growth, Survival, and Fecundity in Black Brant (Branta Bernicla)

“…The correlation between adult body size (PC! scores containing mass) and clutch volume could be spurious if females who nested earlier and laid larger clutches (Cooch 1961, Ryder 1972, Cooper 1978, Ely and Raveling 1984 also gained more mass between hatching and capture in late summer, compared to later nesting females who laid smaller clutches and had less time to gain mass between hatch and capture in late summer. To examine the possibility that mass gain between hatch and recapture in late summer was related to the length of the interval between these events, we regressed mass gain against the number of days between hatch and recapture.…”