jackson@ttidca.TTI.COM (Dick Jackson) (04/12/89)
A year or so ago I saw an article in the New Scientist about "cheating" by some male sea birds -- the male aquires a mate and sets up a nest as usual, but then goes off and pairs up with a second mate, installing her in a second nest at the other end his territory. To settle an argument, could someone please supply solid details, e.g. what kind of bird(s) do(es) this plus references to papers or articles. Much thanks, Dick Jackson Path: ..!{philabs|csun|psivax}!ttidca!ttidcc!jackson jackson@ttidcc.TTI.COM
dmark@cs.Buffalo.EDU (David Mark) (04/16/89)
In article <4235@ttidca.TTI.COM> jackson@ttidca.tti.com (Dick Jackson) writes: >A year or so ago I saw an article in the New Scientist about "cheating" by >some male sea birds -- the male aquires a mate and sets up a nest as >usual, but then goes off and pairs up with a second mate, installing her >in a second nest at the other end his territory. > >To settle an argument, could someone please supply solid details, e.g. what >kind of bird(s) do(es) this plus references to papers or articles. Just about any mating system you could imagine does go on in the world of birds. Even the passerines ("song birds"). A recent issue of _Science_ (31 March 1989, v. 243, no. 4899) has a long article about the British "Hedge Sparrow" (Dunnock), an accentor (Prunellidae). They were found to have a large number of various extra-pair matings, often covert. I recall reading that female American Goldfinches often start a nest with an older male, and once the chicks hatch, they leave that male to look after them, and go off to start a new nest with an inexperienced young male. Homosexual pairings are fairly common among some larger gulls. Female-female pairs often raise young, meaning that they got fertilized somehow (by neighbors). It seems that in gull colonies, if there is an uneven sex ratio, the extras pair up. Many birds organize their mating at "lek"s, the avian equivalent of a singles bar. The males, often in fancy plumage, gather in a common area, and sing, dance, and otherwise carry on. Females approach the lek, check out the dancers, and mate with one each day, until they have completed a clutch of eggs which they then incubate and raise (the young) on their own. This system is widespread, including many grouse, also birds-of-paradise (New Guinea), manakins (Neotropical passerines), some shorebirds (Pectoral Sandpiper, Ruff), and others. In some species, including Phalaropes (small swimming shorebirds), the females are more brightly colored, do the courtship, and after laying the eggs, leave the incubation and chick-rearing to the males. So, while 'monogamous' pairs, and shared rearing of offspring, and fairly common among birds, there are lots and lots of other systems. Males with multiple mates within a single territory must not be all that rare, although I can't think of an example right now. Such systems are, of course, pretty common among mammals, such as fur seals, and many ungulates. Now, maybe someone can answer the original question more directly! David Mark, Professor of Geography (and member, American Ornithologists' Union) dmark@cs.buffalo.edu