American Wildlife Institute.
*Johnsgard, P. A. (1966) “Behavior of the Australian Musk Duck and Blue-billed Duck.”
*Low, G. C., and Marquess of Tavistock (1935) “The Extent to Which Captivity Modifies the Habits of Birds.”
*Lowe, V. T. (1966) “Notes on the Musk Duck
*Munro, J. A. (1941) “Studies of Waterfowl in British Columbia: Greater Scaup Duck, Lesser Scaup Duck.”
O’Brien, R. M. (1990) “Musk Duck,
Oring, L. W. (1964) “Behavior and Ecology of Certain Ducks During the Postbreeding Period.”
*Riggert, T. L. (1977) “The Biology of the Mountain Duck on Rottnest Island, Western Australia.”
Rogers, D. I. (1990) “Australian Shelduck,
OTHER AQUATIC BIRDS
COMMON MURRE
IDENTIFICATION: A gull-sized, web-footed bird with contrasting black upperparts and white underparts; some individuals have a white eye ring. DISTRIBUTION: Northern oceans and adjacent coasts. HABITAT: Marine coasts, bays, islands. STUDY AREAS: Gannet Islands, Labrador, Canada; Skomer Island, Wales; subspecies
LAYSAN ALBATROSS
IDENTIFICATION: A large, white-plumaged, gull-like bird with an enorous wingspan (over 61/2 feet), a dark back, and a grayish black wash on the face. DISTRIBUTION: Northern Pacific Ocean. HABITAT: Oceangoing; breeds on oceanic islands. STUDY AREA: Eastern Island in the Midway Atoll.
Social Organization
Common Murres and Laysan Albatrosses spend eight to nine months of the year at sea (often in large flocks for Murres). The remainder of the time, they gather at traditional nesting sites in extraordinary densities—Murre colonies, for example, can contain hundreds of thousands of pairs. The mating system is a combination of long-term pair-bonds and promiscuous copulations.
Description
A similar form of rape occurs among Laysan Albatrosses. Early in the breeding season, males often leave their partner’s side to try to copulate with males or females that are passing through the breeding colony. This is especially true if they momentarily and inadvertently spread and droop their wings (signals usually given by a female before copulation). Groups of five or six males often pursue the same individual, all jostling to mount him or her; typically a male will hook his bill across the neck of the bird being pursued, to throw it off balance. Homosexual mountings are common in these group rape attempts, and “pile-ups” or stacks of up to four males mounted on top of each other have been observed. Rape attempts—whether on males or females—never result in ejaculation, since the bird being mounted always resists the advances of the pursuing bird. A completely different homosexual activity also occurs in this species: occasionally two birds of the same sex perform an elaborate courtship dance with one another. This complex synchronized display involves more than 25 different postures. The two birds stand facing each other, stretching their heads upward during SKY CALLS and SKY MOOS, clap their bills, and bow, strut, and circle around their partner, all the while making a cacophony of clicking, whinnying, wailing, and grunting sounds.
Nonreproductive and Alternative Heterosexualities
As mentioned above, promiscuous copulations occur frequently in these species. About 10 percent of all Common Murre matings are forced copulations between a male and a female other than his partner, and on some days each female is subjected to such a rape attempt nearly every hour. Females usually respond aggressively to such attacks, and their mates also try to defend them, although sometimes an intruding male will actually disrupt a copulation between a mated pair by knocking the male off his partner’s back. In about 15 percent of all promiscuous matings, the female does not react aggressively and appears to cooperate in allowing the male to make genital contact. Female Laysan Albatrosses always resist rape attempts and may be severely injured in the process: one female was attacked by four different gangs of males in ten minutes, losing an eye and sustaining severe wing injuries. However, forced copulations in this species are always nonprocreative since sperm is never transferred. Many promiscuous matings in Common Murres are nonreproductive as well: cloacal contact often does not occur