58
House Sparrow/Cowbird (Griffin 1959); Savanna Baboon (Marais 1922/1969:214-18); Kestrel (Olsen 1985). Regarding the House Sparrow/Cowbird case, a number of subsequent researchers (e.g., Selander and LaRue 1961; Rothstein 1980) have also interpreted this behavior as “aggression” or “appeasement.” Aside from the fact that the activity involving homosexual mounting is not identical to strictly “aggressive” or “preening invitation” displays in Cowbirds (cf. Laskey 1950), a “nonsexual” interpretation cannot explain why Cowbirds “tolerate” homosexual mountings from Sparrows and even actively solicit them. Moreover, the function(s) of these “head-down” displays remain controversial and speculative independent of any homosexual activity (cf. Scott and Grumstrup-Scott 1983). Specific arguments against an “aggressive” or “appeasement” interpretation of these types of behaviors (regardless of whether any same-sex mounting is involved) are presented in Verbeek, N. A. M., R. W. Butler, and H. Richardson (1981) “Interspecific Allopreening Solicitation in Female Brewer’s Blackbirds,”
59
Chaffinch (Marjakangas 1981); Regent Bowerbird (Phillipps 1905; Marshall 1954). Similarly, early reports of courtship activity between male Swallow-tailed Manakins by Sick (1959, 1967) were discounted by Foster (1981:174), who tried to claim that the younger male birds being courted by adult males were actually females that had malelike plumage or were male observers or participants in nonsexual aggressive displays. However, Sick (1959:286) verified the male sex of these birds by dissecting them, and he stated explicitly (Sick 1967:17) that no aggression was involved in the displays. Moreover, it is clear from his descriptions (Sick 1959:286) that the display type that Foster (1981) claimed was aggressive occurs in the absence of younger males, not in their presence. Foster’s categorization of such displays as aggressive also appears to be based primarily on the fact that they occur between males, rather than on any inherent differences in the behaviors: as Foster (1981:172; 1984:58) admits, such displays are “extremely similar to” and “strongly reminiscent” of courtship behaviors. That Foster was unable to directly observe courtship displays of the type that Sick reported between males may also be due to geographic or subspecies differences in behaviors: Sick studied a population in Brazil while Foster observed birds in Paraguay. Other elements of the courtship displays between the two populations do appear to differ significantly, such as the vocalizations used and the direction in which males fly during the display (in Brazil, the male farthest from the courted bird begins the courtship “wheel,” while in Paraguay the bird closest to the courted bird begins). It should also be pointed out that Snow (1963) independently observed courtship between males in the closely related Blue- backed Manakin.
60
Vasey “Homosexual Behavior in Primates,” p. 197; for a similar observation, see Wolfe, “Human Evolution and the Sexual Behavior of Female Primates,” p. 130.
61
Hyde, H. M. (1970)
62
Killer Whale (Balcomb et al. 1979:23); published version: Balcomb, K. C., III, J. R. Boran, R. W. Osborne, and N. J. Haenel (1980) “Observations of Killer Whales (
63
Musk-ox (Smith 1976; Tener 1965; Reinhardt 1985); Walrus (Miller 1976); Harbor Seal (Johnson 1974, 1976; Johnson and Johnson 1977).
64
Halls, L. K., ed., (1984)
65
Woodpeckers (Short 1982; Winkler et al. 1995); Skutch, A. F. (1985)
66
See, for example, Fay (1982) on Walruses, Birkhead (1991) on Magpies, Lowther and Cink (1992) on House Sparrows, Davis (1993) on Black-crowned Night Herons, Lowther (1993) on Brown-headed Cowbirds, Telfair (1994) on Cattle Egrets, Burger (1996) on Laughing Gulls, Russell (1996) on Anna’s Hummingbirds, and Ciaranca et al. (1997) on Mute Swans.
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Hooded Warbler (Niven 1993:190); Antbirds (Willis 1967, 1972, 1973); Orange-fronted Parakeet (Buchanan 1966); Golden Plover (Nethersole-Thompson and Nethersole-Thompson 1961, 1986); Mallard Duck (Lebret 1961); Black Swan (Braithwaite 1970, 1981); Scottish Crossbill (Nethersole-Thompson 1975); Black-billed Magpie (Baeyens 1981a); Pied Kingfisher (Moynihan 1990). Similar statements have been made by Konrad Lorenz (1991:241 [Greylag Goose]), who claimed that long-term pair-bonding between males only occurs in Geese and Ducks; and Hunt and Hunt (1977:1467 [Western Gull]), who were unaware of any previous reports of homosexual pairing in wild birds.
68
Black-headed Gull (van Rhijn and Groothuis 1985:165; Kharitonov and Zubakin 1984); Adelie Penguin (Davis et al. 1998:136); Humboldt Penguin (Scholten 1992:8); Kestrel (Olsen 452). Similar statements have been issued by scientists studying other species—Sylvestre (1985:64), for example, reported not being aware of any previous records of homosexual activity in Botos, even though fairly extensive descriptions were available in Layne and Caldwell (1964), Caldwell et al. (1966), Spotte (1967), and Pilleri et al. (1980). Walther (1990:308) claimed that courtship betweeen male hoofed mammals had not been observed in the wild, when in fact such behavior had been reported in numerous prior studies, including in Pronghorn, Blackbuck, Mountain Sheep (Bighorn, Thinhorn, Asiatic Mouflon), Mountain Goats, Musk-oxen, Bharal, and Markhor (Walther, F. R. [1990] “Bovids: Introduction,” in
69
See, for example, Takahata et al. (1996:149), who ask, “Is GG-rubbing a sexual behavior?” and conclude that its “nonsexual” aspects are more prominent, because of its association with tension reduction, feeding, reassurance, participation by nonestrous females, and the fact that Bonobos (unlike Japanese Macaques) do not form “exclusive homosexual female-female pairs.” None of these characteristics, in fact, negate a fully “sexual” interpretation. In particular, the fact that Bonobos do not form same-sex pairs or consortships hardly argues against the sexual nature of their genital rubbing—it simply indicates that homosexual interactions in this species do not involve extensive pair-bonding. By these criteria, Bonobo heterosexual interactions would have to be considered nonsexual as well, since they are often associated with the same “social” or “nonsexual” situations, nor do individuals form “exclusive heterosexual male-female pairs.” See also Kuroda (1980:190), who considers genital rubbing between females to be “uninterpretable” when it occurs in contexts that are not related to tension reduction or food exchange; and Kano (1980:253—54, 1992:139,1990:66—67, 69), who classifies same-sex activities in Bonobos as primarily “social” rather than “sexual” and ascribes to them the primary “functions” of greeting, reassurance, reconciliation, and food-sharing (while nevertheless recognizing that sexual aspects may be secondarily involved in some cases). As recently as 1997, researchers were still speculating about, and emphasizing, the nonsexual “functions” of Bonobo homosexual activity (Hohmann and Fruth 1997).
