Bruce Bagemihl - Biological Exuberance

Orientation: Male Gray-capped Social Weavers that copulate with other males also mate and pair with females (and in fact may engage in homosexual activity while they are heterosexually paired). The same is true for some Sociable Weavers, although most males in this species mount both males and females, even if they are not paired. However, relatively few males participate in full heterosexual copulations, and those that do appear to have higher rates of homosexual activity as well. To the extent that they court or attempt to mount both males and females, some male Bishops are also bisexual. However, the males they pursue are usually indifferent, at best, to their approaches, indicating perhaps a more heterosexual orientation on their part.

In Gray-capped Social Weavers (and occasionally in Sociable Weavers), nonbreeding birds often help heterosexual pairs build their nest and feed their young. Some of these “helpers” are the pairs’ young from a previous season who are delaying their own reproductive careers, while others are fully adult birds (who help out in about 18 percent of all feedings). Some nonbreeding youngsters, however, do not help their parents. Sociable Weavers may participate in nonmonogamous heterosexual mountings (in addition to the homosexual matings described above). Although most birds are probably faithful to their partners, some males in captivity have been observed mounting and copulating with females other than their mates. Female Red Bishops occasionally refuse to allow a male to mount them, vigorously pecking and displaying threat postures to repel him. In addition, males often court Bishops of other species, who are not usually attracted by such interspecies displays. Finally, female Red Bishops have been observed cannibalizing both their own and others’ nests, eating some or all of the eggs.

Adult male Red-shouldered Widowbirds ( Euplectes axillaris ) also sometimes court younger males.

*asterisked references discuss homosexuality/transgender

*Collias, E. C, and N. E. Collias (1980) “Individual and Sex Differences in Behavior of the Sociable Weaver Philetairus socius .” In D. N. Johnson, ed., Proceedings of the Fourth Pan-African Ornithological Congress ( Seychelles , 1976), pp. 243—51. Johannesburg: Southern African Ornithological Society.

*———(1978) “Nest Building and Nesting Behavior of the Sociable Weaver Philetairus socius .” Ibis 120:1—15.

*Collias, N. E., and E. C. Collias (1980) “Behavior of the Gray-capped Social Weaver ( Psuedonigrita arnaudi ) in Kenya.” Auk 97:213—26.

Craig, A. J. F. K. (1982) “Mate Attraction and Breeding Success in the Red Bishop.” Ostrich 53:246-48.

*———(1980) “Behavior and Evolution in the Genus Euplectes .” Journal für Ornithologie 121:144—61.

*———(1974) “Reproductive Behavior of the Male Red Bishop Bird.” Ostrich 45:149—60.

Craig, A. J. F. K., and A. J. Manson (1981) “Sexing Euplectes Species by Wing-Length.” Ostrich 52:9—16.

Maclean, G. L. (1973) “The Sociable Weaver.” Ostrich 44:176—261.

Roberts, C. (1988) “Little Bishop Birds ( Euplectes orix ) in a Lafia Garden—Tom, Dick, Harry, and Fred.” Nigerian Field 53:11—22.

Skead, C. J. (1959) “A Study of the Redshouldered Widowbird Coliuspasser axillaris axillaris (Smith).” Ostrich 30:13—21.

———(1956) “A Study of the Red Bishop.” Ostrich 27:112—26.

Woodall, P. F. (1971) “Notes on a Rhodesian Colony of the Red Bishop.” Ostrich 42:205—10.

IDENTIFICATION: The familiar black-bibbed sparrow; Cowbird is iridescent black with a dark brown head. DISTRIBUTION: Throughout most of North and South America, Eurasia (House Sparrow); North and Central America (Cowbird). HABITAT: Woodland, prairie, farmland, human habitation. STUDY AREAS: Near Stillwater, Oklahoma, and Long Island, New York; subspecies M.a. ater and M.a. artemisiae.

IDENTIFICATION: Light gray plumage, black wings and tail, and (in some birds) bare yellow head and fleshy black wattles. DISTRIBUTION: Eastern and southern Africa. HABITAT: Savanna, grassland, woodland. STUDY AREAS: University of Mainz and in Nieder-Olm, Germany.

Wattled Starlings usually associate in small, nomadic flocks, although up to a thousand birds may gather together to pursue locust swarms. Similarly, breeding colonies may contain thousands of nests when locusts are available, but usually birds nest in smaller groups containing a maximum of 400 pairs. Most individuals form monogamous pair-bonds, as do House Sparrows (who also generally nest in colonies). Brown-headed Cowbirds have a highly variable mating system: in many populations birds form (usually monogamous) pair-bonds, while in others they are promiscuous or form polygamous bonds with several individuals.

Behavioral Expression: Male Brown-headed Cowbirds sometimes solicit homosexual copulations from male House Sparrows. Cowbirds commonly invite birds of other species to preen them, but occasionally an interspecies encounter includes homosexual mounting when a House Sparrow is involved. This extraordinary behavior typically begins with a male Cowbird adopting a characteristic HEAD-DOWN posture next to a Sparrow, in which he bows his head, touching his lower bill to his breast feathers while crouching slightly and raising his wings a bit at the shoulders. The House Sparrow then mounts the Cowbird, grasping his head feathers in his beak while attempting to copulate. If he shows signs of leaving or lack of interest after a single mounting, the Cowbird will immediately resume the invitation posture next to him, insistently nudging the Sparrow with his head and persistently following him until he mounts again. This may continue for an extended time, with repeated homosexual mountings (five or more) occurring in a single session.

Homosexual courtships occasionally occur in Wattled Starlings. Males sometimes select another male as the object of their attentions, displaying to him with a number of stylized postures. Among these are the LATERAL DISPLAY, in which the male turns sideways and lets his wings hang down at his side (exposing their white feathers); the FRONTAL DISPLAY, where the courting male fluffs up his belly and back feathers, raising and quivering his wings while spreading his tail; and the distinctive VULTURE POSTURE, in which he stretches his entire body vertically while puffing out his breast feathers and tightly folding his wings against his sides like a vulture. A form of plumage transvestism also occurs in this species, in which some females develop a male appearance. Most males have a special seasonal nuptial plumage, growing two pendulous wattles from either side of their beaks and losing most of the feathers from their head, thereby exposing the yellow or black skin and two fleshy, comblike growths on the forehead. This feather loss has even been described as a form of “male pattern baldness” akin to the type of hair loss found in humans, and indeed it is regulated by male hormones (as is human baldness). While the majority of females never exhibit these plumage characteristics, a few females do acquire a male appearance with feather loss, wattles, and combs.