IDENTIFICATION: A pheasant-sized bird with brownish gray plumage, powerful legs and claws, and long, ornate tail feathers. DISTRIBUTION: Southeastern Australia. HABITAT: Rain forest, eucalyptus, other forests. STUDY AREAS: Sherbrooke Forest near Melbourne, Australia; Adelaide Zoo, South Australia.
Social Organization
Adult male Superb Lyrebirds establish territories on which they build earth mounds three to five feet wide, used as platforms for courtship displays. The mating system is polygamous or promiscuous: birds mate with multiple partners without developing long-lasting pair-bonds, and males do not contribute to raising their offspring. Adolescent Lyrebirds often associate in small groups, sometimes consisting only of males.
Description
Adolescent male Lyrebirds also sometimes mount one another as well as particpate in homosexual courtship displays. Courtship between younger males is usually mutual, with both birds singing and displaying to one another. Occasionally an adult and an adolescent male also engage in mutual display, and adult females (in captivity) have been observed performing a similar courtship display to each other. Typically, the two adolescent males circle around each other on a display mound, tails raised in a fan shape with their feathers intermingled and beaks nearly touching while performing a vocal duet. One male may also perform a full-face or invitation display, and his partner sometimes runs underneath his outstretched tail the way a female does during heterosexual courtship. Sometimes the two males engage in what appears to be a form of COURTSHIP-FEEDING: in response to begging from his partner, one male regurgitates a worm or other food item as an offering to the other, who promptly eats it. This behavior appears to be unique to homosexual courtships. Two younger males often form a “companionship”: in addition to courting each other, they follow one another, feed together (even digging in the same hole for food items), roost next to each other, and share bathing pools. These male pair-bonds usually last for only a few days, and adolescent males often form multiple serial attachments of this sort.
Nonreproductive and Alternative Heterosexualities
Male and female Superb Lyrebirds lead largely separate lives. Other than brief encounters during the breeding season for courtship and copulation, the two sexes rarely interact: only about 8—10 percent of all Lyrebird sightings are of males and females together. Because males do not contribute at all to parenting, incubation and chick-raising often become burdensome for females—and by extension, potentially harmful for the eggs and/or chicks. During the early stages of incubation, females regularly leave their eggs unattended during the day for up to seven hours at a time to feed, causing the egg temperature to drop dramatically. Overall, females are relatively “inattentive” parents, incubating their eggs for only about 27—45 percent of the available daylight hours; this is significantly less than in other perching birds, who generally spend 60—80 percent. Because the eggs are laid and incubated during the coldest months of winter, they are consequently exposed to dangerously low (sometimes even sub-freezing) temperatures that generally slow embryonic development. After hatching, nestlings occasionally die from overexposure when their mother has been away from the nest for too long.
Kenyon, R. F. (1972) “Polygyny Among Superb Lyrebirds in Sherbrooke Forest Park, Kallista, Victoria.”
Lill, A. (1986) “Time-Energy Budgets During Reproduction and the Evolution of Single Parenting in the Superb Lyrebird.”
*———(1979a) “An Assessment of Male Parental Investment and Pair Bonding in the Polygamous Superb Lyrebird.”
———(1979b) “Nest Inattentiveness and Its Influence on Development of the Young in the Superb Lyrebird.”
Reilly, P. (1988)
*Smith, L. H. (1996-97) Personal communication.
*———(1988)
(1982) “Molting Sequences in the Development of the Tail Plumage of the Superb Lyrebird,
*———(1968)
Watson, I. M. (1965) “Mating of the Superb Lyrebird,
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