Bruce Bagemihl - Biological Exuberance

*asterisked references discuss homosexuality/transgender

Cramp, S., and K. E. L. Simmons, eds. (1983) “Black-winged Stilt ( Himantopus himantopus ).” In Handbook of the Birds of Europe, the Middle East, and North Africa, vol. 3, pp. 36-47. Oxford: Oxford University Press.

Goriup, P. D. (1982) “Behavior of Black-winged Stilts.” British Birds 75:12–24.

Hamilton, R. B. (1975) Comparative Behavior of the American Avocet and the Black-necked Stilt (Recurvirostridae). Ornithological Monographs no. 17. Washington, DC: American Ornithologists’ Union.

Kitagawa, T. (1989) “Ethosociological Studies of the Black-winged Stilt Himantopus himantopus himantopus. I. Ethogram of the Agonistic Behaviors.” Journal of the Yamashina Institute of Ornithology 21:52–75.

*———(1988a) “Ethosociological Studies of the Black-winged Stilt Himantopus himantopus himantopus. III. Female-Female Pairing.” Japanese Journal of Ornithology 37:63–67.

———(1988b) “Ethosociological Studies of the Black-winged Stilt Himantopus himantopus himantopus. II. Social Structure in an Overwintering Population.” Japanese Journal of Ornithology 37:45—62.

*Pierce, R. J. (1996a) “Recurvirostridae (Stilts and Avocets).” In J. del Hoyo, A. Elliott, and J. Sargatal, eds., Handbook of the Birds of the World, vol. 3: Hoatzin to Auks, pp. 332—47. Barcelona: Lynx Edicións.

———(1996b) “Ecology and Management of the Black Stilt Himantopus novaezelandiae.” Bird Conservation International 6:81–88.

(1986) Black Stilt. Endangered New Zealand Wildlife Series. Dunedin, New Zealand: John McIndoe and New Zealand Wildlife Service.

*Reed, C. E. M. (1993) “Black Stilt.” In S. Marchant and P. J. Higgins, eds., Handbook of Australian, New Zealand, and Antarctic Birds, vol. 2, pp. 769—80. Melbourne: Oxford University Press.

IDENTIFICATION: A large (17 inch), stocky shore bird with black upperparts, white underparts, and red-orange bill, eyes, and legs. DISTRIBUTION: Throughout Eurasia; winters in Africa, Middle East, southern Asia. HABITAT: Beaches, salt marshes, rocky coasts, mudflats. STUDY AREAS: The islands of Texel, Vlieland, and Schiermonnikoog, the Netherlands; subspecies H.o. ostralegus .

IDENTIFICATION: A medium-sized (10 inch) sandpiper-like bird with mottled buff and black plumage; adult males have a black face and underparts bordered with white. DISTRIBUTION: Northern Europe; winters south to Mediterranean and North Africa. HABITAT: Tundra, bogs, moors, heath. STUDY AREA: Dorback Moor, Scotland; subspecies P.a. apricaria.

Oystercatchers and Golden Plovers commonly associate in flocks. The mating system typically involves monogamous pair-bonding, although many alternative arrangements also occur (see below). Nonbreeding Oystercatchers tend to aggregate in groups known as CLUBS.

Behavioral Expression: Oystercatchers sometimes participate in same-sex courtship and copulation. This behavior typically occurs within bisexual trios, that is, an association of three birds—two of one sex and one of the other—in which all three members have a bonded sexual relationship. For example, two males and a female sometimes form a trio, and in addition to heterosexual activity between the opposite-sex partners, the two males may court and mount each other. Several different courtship and pair-bonding displays are used in both same-sex and opposite-sex contexts. For example, while walking around each other, two males might perform BALANCING, in which they make seesaw movements with their bodies, or the THICK-SET ATTITUDE, a stylized posture in which the head is drawn down between the shoulders with the tail and back horizontal, all the while bending the legs and making tripping steps. Sometimes two males also perform ritualized nest-building activities as part of their mutual courtship, such as THROWING STRAWS, in which they toss straw and other materials backward, or PRESSING A HOLE, in which they repeatedly sit down, pressing their breasts and wings against the ground as if fashioning a nest. As a prelude to copulation, one male approaches the other in the STEALTHY ATTITUDE, similar to the thick-set attitude except that the head is held to one side and the tail is pressed down and spread. One male may mount and try to copulate with the other, although sometimes his sexual advances are thwarted by an attack from the other male. Interestingly, all three members of such a trio may be nonmonogamous, engaging in heterosexual courtship or copulations with birds other than their primary partners.

Homosexual activities also occur between two female Oystercatchers that form part of a bisexual trio with a male. Most associations of this type start off the way heterosexual trios do, with considerable aggression between the females, but eventually they develop a strong bond with each other. They preen one another while remaining close together and also cooperate (along with their male partner) in mutual defense of their territory. Employing the same behavior patterns seen in heterosexual mating, the two females also regularly copulate with one another: one female approaches the other in a hunched posture, making soft pip-pip noises while her partner tosses her tail upward. Then, while mounting, the female flaps her wings to maintain balance and may push her tail under the other female’s in order to achieve genital (cloacal) contact, at which point she utters soft wee-wee sounds. The two birds may take turns mounting one another, and about 47 percent of lesbian copulations include full genital contact (compared to 67 percent of matings by heterosexual pairs and 74 percent of male-female copulations in heterosexual trios). The females also mate regularly with their male partner, eventually building a joint nest together in which they each lay eggs. This results in a SUPERNORMAL CLUTCH of up to 7 eggs (compared to a maximum of 4–5 in nests of heterosexual pairs, or in each of the two separate nests of heterosexual trios). All three partners take turns incubating the eggs and they cooperate in raising their chicks. However, because each bird is usually unable to adequately cover all 7 eggs simultaneously, bisexual trios generally hatch and raise fewer offspring than do heterosexual pairs. Bisexual trios can remain together for up to 4–12 years, comparable to Oystercatcher heterosexual pairs, and are actually more stable and longer-lasting than heterosexual trios (which typically do not extend beyond 4 years).

Male Golden Plovers occasionally court and pair with each other in the early spring. Courtship activities often begin with ground displays, in which one male chases the other with his head lowered, wings half-spread, and back feathers ruffled, all the while raising and lowering his fanned tail. This may develop into a spectacular twisting aerial pursuit flight, in which the two males synchronously dip and climb, careening and skimming over the ground in a dramatic, high-speed chase that may take them far from their home territories.

Frequency: Homosexual behavior occurs occasionally in Oystercatcher and Golden Plover populations. Less than 2 percent of Oystercatchers, for example, live in trios of two females with one male, although 43 percent of such associations involve homosexual bonding and sexual activities. Overall, about 1 in every 185 copulations is between two females; lesbian matings take place roughly once every 6–7 hours within each bisexual trio, compared to roughly once every 3–6 hours for heterosexual matings (in a pair or trio). Likewise, approximately 1 out of every 400 Oystercatcher bonds involves a trio of two males with a female, and only some of these include same-sex activity. As in bisexual trios with two females, however, homosexual behavior may be fairly frequent within the association: in one such trio, for instance, almost two-thirds of all courtship activities were homosexual, and 15— 19 percent of all mounting activities were same-sex.