Biological Exuberance: Animal Homosexuality and Natural Diversity

Redshanks (and up to a quarter of Greenshanks) change partners between or within breeding seasons (this is more common among males), and only about a third of all males and half of all females mate for life. Some birds may divorce and re-pair with up to four different partners during their lives. In a few cases, female Redshanks have even left their mate to pair with another male, only to return to their “ex” the following season and remain with him for many more years. Adoption or foster-parenting also takes place in Redshanks: females sometimes lay eggs in other females’ nests (who then raise all the chicks as their own), and Redshanks have even been seen taking care of chicks of other species of shorebirds, such as the avocet (Recurvirostra avosetta).

Some Greenshanks do not participate in breeding at all—about a quarter of all males, on average, do not procreate (and in some years this figure may be higher—nearly half of all males). This includes both single birds and those that are heterosexually paired but do not breed. Such nonbreeding pairs constitute an average of more than 15 percent of pairs, though in some years more than a third do not reproduce. Heterosexual relations may also be marked by unwillingness and aggression between the sexes: female Redshanks sometimes turn on males that are chasing them during courtship, staving off their advances with prolonged fights involving much pecking and scratching. Females of both species may also refuse to allow males to mount them: about a third of all Redshank heterosexual mating attempts, for example, are not completed due to female refusal.

Sources

*asterisked references discuss homosexuality/transgender

*Cramp, S., and K. E. L. Simmons (eds.) (1983) “Redshank (Tringa totanus).” In Handbook of the Birds of Europe, the Middle East, and North Africa, vol. 3, pp. 531—35. Oxford: Oxford University Press.

Garner, M. S. (1987) “Lesser Yellowlegs Attempting to Mate with Redshank.” British Birds 80:283.

Hakansson, G. (1978) “Incubating Redshank, Tringa totanus, Warming Young of Avocet, Avocetta recurvirostra.” Var Fagelvarld 37:137—38.

*Hale, W. G. (1980) Waders. London: Collins.

*Hale, W. G., and R. P. Ashcroft (1983) “Studies of the Courtship Behavior of the Redshank Tringa totanus.” Ibis 125:3—23.

*———(1982) “Pair Formation and Pair Maintenance in the Redshank Tringa totanus.” Ibis 124:471—501.

*Nethersole-Thompson, D. (1975) Pine Crossbills: A Scottish Contribution. Berkhamsted: T. and A. D. Poyser.

*———(1951) The Greenshank. London: Collins.

*Nethersole-Thompson, D., and M. Nethersole-Thompson (1986) Waders: Their Breeding, Haunts, and Watchers. Calton: T. and A. D. Poyser.

*———(1979) Greenshanks. Vermillion, S.D.: Buteo Books.

Thompson, D. B. A., P. S. Thompson, and D. Nethersole-Thompson (1988) “Fidelity and Philopatry in Breeding Redshanks (Tringa totanus) and Greenshanks (T. nebularia).” In H. Ouellet, ed., Acta XIX Congressus Internationalis Ornithologici (Proceedings of the 19th International Ornithological Congress), 1986, Ottawa, vol. I, pp. 563—74. Ottawa: University of Ottawa Press.

———(1986) “Timing of Breeding and Breeding Performance in a Population of Greenshanks (Tringa nebularia).” Journal of Animal Ecology 55:181—99.

BLACK-WINGED STILT

IDENTIFICATION: A fairly large (12—15 inch) sandpiper-like bird with long pink legs, white plumage with black wings and back, and a slender black bill. DISTRIBUTION: Throughout much of Australasia, Europe, Africa, Central and South America, western and southern United States. HABITAT: Tropical and temperate wetlands. STUDY AREAS: Gyotuku Sanctuary, Ichikawa City, Japan; Morocco and the Belgium/Netherlands border area; subspecies H.h. himantopus.

BLACK STILT

IDENTIFICATION: Similar to Black-winged Stilt but with entirely black plumage. DISTRIBUTION: New Zealand; critically endangered. HABITAT: Rivers, lakes, swamps. STUDY AREA: Mackenzie Basin, South Island, New Zealand.

Social Organization

The primary social unit among Stilts is the monogamous mated pair; Black-winged couples often nest in loose colonies containing 2—50 families, while Black Stilts are less gregarious. Outside of the mating season, the birds gather in flocks of usually up to ten individuals, although assemblies of hundreds of Black-winged Stilts may also occur.

Description

Behavioral Expression: Lesbian pairs occur in both Black- winged and Black Stilts. In these partnerships, two females participate in courtship, copulation, and parenting activities together. Homosexual pairing and courtship in Black-winged Stilts often begins with a ritual NEST DISPLAY activity: each female takes turns symbolically “showing” the other a nest location by squatting on land as if she were incubating eggs, and making pecking motions in the mud as though she were turning the eggs over. Although heterosexual pairings also frequently commence with this activity, in lesbian pairs the two birds may spend considerably more time engaged in nest display. This may lead to full-scale courtship activities, such as DIBBLING —bill dipping and shaking by both partners, involving prominent splashing of water—and ritual preening, in which one female preens the side of her breast nearest to the other female, frequently combined with more splashing activity. Often one female takes up the NECK EXTENDED posture, a stylized pose in which she stands with her legs slightly apart and her neck lowered and extended just above the surface of the water. While one female is standing in this position, the other performs a courtship dance in which she moves back and forth behind her partner, striding in semicircles from one side to the other. The two females may participate in continuous courtship activities for up to three-quarters of an hour at a time. Sexual activity also takes place between members of a lesbian pair, with one female mounting the other as in heterosexual copulation.

Once bonded, the pair vigorously defends their territory against any intruding families and eventually builds a nest together. Because both females sometimes lay eggs, the nests of lesbian pairs often contain SUPERNORMAL CLUTCHES of 7—8 eggs, up to twice as many as those of heterosexual pairs (which usually have only 3—4 eggs). Both females take turns incubating the eggs; in heterosexual pairs the two birds also share incubation duties, but in many cases the female contributes a disproportionately greater amount of time than does the male. If the eggs are eaten by predators, the lesbian pair replaces them by laying a second clutch (as often happens with heterosexual parents as well). Most eggs laid by same-sex pairs are probably infertile. Like heterosexual pairs, some Black- winged Stilt lesbian pairs divorce. This may occur, for example, when one female forms a new pair-bond with another female. Although mate-switching may initially be accompanied by aggression between the separating females, the divorced partner sometimes still remains “friends” with the new pair, being allowed to visit their territory (unlike other birds, which are routinely chased away).

A nest with a “supernormal clutch” of eggs belonging to a pair of female Black-winged Stilts in Japan

Frequency: In Black-winged Stilts, female pairs may constitute anywhere from 5—17 percent of the total number of pairs (depending on the population), while about 2 percent of Black Stilt pairings are lesbian. Homosexual copulation occurs at fairly high rates in some Black-winged Stilt female