Snow Goose females also occasionally “abandon” their eggs by laying in what are known as DUMP NESTS, which contain large numbers of unincubated eggs from many different females. Abandonment of nests may also be triggered by the stresses of reproduction: females can lose up to a third of their body mass while incubating, and some individuals desert their clutches or even starve on the nest as a result of such hardships. Most Snow Goose nesting colonies also have a nonbreeding flock on their peripheries. In some years, the proportion of nonbreeding adults is sizable—as much as 40 percent of the population—and occasionally an entire colony will forgo breeding (for example if the weather is particularly adverse). Many Canada Goose heterosexual pairs are nonbreeding as welclass="underline" in some populations, for example, more than a quarter of all male-female pairs do not procreate, although they may copulate frequently. In fact, some nonbreeders have sexual activity rates that are almost twice as high as pairs that do reproduce.
Sources
*asterisked references discuss homosexuality/transgender
*Allen, A. A. (1934) “Sex Rhythm in the Ruffed Grouse (Bonasa umbellus Linn.) and Other Birds.” Auk 51:180–99.
Ankney, C. D., and C. D. MacInnes (1978) “Nutrient Reserves and Reproductive Performance of Female Lesser Snow Geese.” Auk 95:459–71.
*Collias, N. E., and L. R. Jahn (1959) “Social Behavior and Breeding Success in Canada Geese (Branta canadensis) Confined Under Semi-Natural Conditions.” Auk 76:478-509.
*Conover, M. R. (1989) “What Are Males Good For?” Nature 342:624–25.
Cooke, E, and D. S. Sulzbach (1978) “Mortality, Emigration, and Separation of Mated Snow Geese.” Journal of Wildlife Management 42:271-80.
Cooke, F., M. A. Bousfield, and A. Sadura (1981) “Mate Change and Reproductive Success in the Lesser Snow Goose.” Condor 83:322–27.
*Diamond, J. M. (1989) “Goslings of Gay Geese.” Nature 340:101.
Ewaschuk, E., and D. A. Boag (1972) “Factors Affecting Hatching Success of Densely Nesting Canada Geese.” Journal of Wildlife Management 36:1097–106.
*Grether, G. F., and A. M. Weaver (1990) “What Are Sisters Good For?” Nature 345:392.
*Klopman, R. B. (1962) “Sexual Behavior in the Canada Goose.” Living Bird 1:123–29.
Lank, D. B., P. Mineau, R. F. Rockwell, and F. Cooke (1989) “Intraspecific Nest Parasitism and Extra-Pair Copulation in Lesser Snow Geese.” Animal Behavior 37:74-89.
Luekpe, K. (1984) “A Strange Goose: Canada-Snow Hybrid?” Passenger Pigeon 46:92.
MacInnes, C. D., R. A. Davis, R. N. Jones, B. C. Lieff, and A. J. Pakulak (1974) “Reproductive Efficiency of McConnell River Small Canada Geese.” Journal of Wildlife Management 38:686–707.
Martin, K., F. G. Cooch, R. F. Rockwell, and F. Cooke (1985) “Reproductive Performance in Lesser Snow Geese: Are Two Parents Essential?” Behavioral Ecology and Sociobiology 17:257–63.
*Mineau, P., and F. Cooke (1979) “Rape in the Lesser Snow Goose.” Behavior 70:280–91.
Nastase, A. J., and D. A. Sherry (1997) “Effect of Brood Mixing on Location and Survivorship of Juvenile Canada Geese.” Animal Behavior 54:503–7.
Prevett, J. P. and C. D. MacInnes (1980) “Family and Other Social Groups in Snow Geese.” Wildlife Monographs 71:1–46.
*Quinn, T. W., J. C. Davies, F. Cooke, and B. N. White (1989) “Genetic Analysis of Offspring of a Female-Female Pair in the Lesser Snow Goose (Chen c. caerulescens).” Auk 106:177–84.
*Starkey, E. E. (1972) “A Case of Interspecific Homosexuality in Geese.” Auk 89:456–57.
Syroechkovsky, E. V. (1979) “Podkladyvaniye byelymi gusyami yaits v chuzhiye gnyezda [The Laying of Eggs by White Geese into Strange Nests].” Zoologichesky Zhurnal 58:1033—41.
Williams, T. D. (1994) “Adoption in a Precocial Species, the Lesser Snow Goose: Intergenerational Conflict, Altruism, or a Mutually Beneficial Strategy?” Animal Behavior 47:101–7.
Zicus, M. C. (1984) “Pair Separation in Canada Geese.” Wilson Bulletin 96:129–30.
BLACK SWAN
IDENTIFICATION: The only swan with fully black plumage; wing feathers are white, bill is bright red, and the neck is especially long. DISTRIBUTION: Australia, Tasmania, New Zealand. HABITAT: Lakes, lagoons, swamps, bays, floodlands. STUDY AREAS: Lake George and Lake Bathurst, New South Wales, Australia; in captivity at the Division of Wildlife Research, Canberra, Australia.
MUTE SWAN
IDENTIFICATION: A large swan (up to 33 pounds) with a black knob at the base of its reddish orange bill (less prominent in females). DISTRIBUTION: Europe and temperate Asia. HABITAT: Marshes, ponds, lakes, slow-moving rivers, lagoons, coastal areas. STUDY AREAS: Abbotsbury (Dorset) and Rainworth Lodge (Notts), England; Renfrewshire, Scotland.
Social Organization
Black Swans sometimes flock by the thousands and usually form mated pairs (although with numerous variations—see below) that nest either colonially or in separate territories. Mute Swans also generally develop long-term, monogamous bonds and nest in widely spaced territories, although some pairs form nesting colonies. Outside of the breeding season, they often associate in flocks.
Description
Behavioral Expression: Some male Black Swans form stable, long-lasting homosexual pairs. Like heterosexual mates, same-sex partners often remain together for many years. The two males frequently perform the GREETING CEREMONY, a pair-bonding display that helps solidify and reinforce their partnership: the birds face one another, raise their wings (sometimes flapping them to expose the white feathers), and call repeatedly while extending their necks and lifting their bills up. Males in homosexual pairs also perform a courtship behavior known as HEAD-DIPPING. In this display—a prelude to copulation—the two birds repeatedly immerse first the head, then the neck, and finally the body in a wavelike fashion, sometimes for extended periods of 20–25 minutes. This can lead to homosexual mounting, although if one male does not want to participate in sexual activity he may respond aggressively to his partner’s overtures.