{"id":7904,"date":"2015-01-05T19:09:44","date_gmt":"2015-01-06T03:09:44","guid":{"rendered":"https:\/\/ornithology.com\/?page_id=7904"},"modified":"2024-12-30T23:30:59","modified_gmt":"2024-12-31T07:30:59","slug":"reproduction","status":"publish","type":"page","link":"https:\/\/ornithology.com\/ornithology-lectures\/reproduction\/","title":{"rendered":"Reproduction"},"content":{"rendered":"

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0<\/span><\/p>\n

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Eared Grebes courting<\/figcaption><\/figure>\n

Most birds are monogamous but polygamy (polyandry = many males\/one female, e.g. phalaropes and polygyny = many females\/one male e.g.<\/em> RW Blackbirds) are not uncommon. Promiscuous birds will mate with anybody of the opposite sex of the same species ( e.g.<\/em> Brown-headed Cowbirds).<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0The birds may court and pair up during the winter (e.g.<\/em> waterfowl) or find each other at the breeding grounds (most birds). The duration of the pair bond varies from one season to the next. Even as little as one copulation may be the extent of the pair bond; or the pair bond may last the life of an individual. If the same pair does nest year after year, it may be due more to the attractiveness of the territory or nest site rather than each other. Reliable evidence for true lifetime mating is scarce – it is hard to collect that kind of data. But there is some evidence for lifetime mating among eagles, wrentits, European nuthatches, the Brown Creeper, and lyrebirds.<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Some pairs mate for several seasons while other pairs find new mates; this is true within one species as well as among species.<\/span><\/p>\n

Pair bonds<\/span><\/span><\/p>\n

1. Long term or life is only one type.
\n<\/span>2. The sexes may remain together only for the breeding season, usually until the young have been raised ; most birds.
\n<\/span>3. The sexes may remain together for weeks or months during courtship but separate when incubation begins: most ducks.
\n<\/span>4. The sexes may remain together for only a few days or until incubation begins<\/span>: RT Hummingbird, Philippine Weaverbird, Northern Phalarope.
\n<\/span>5. Or the sexes may meet only for copulation: grouse, Prairie Chicken, Ruff.<\/span><\/p>\n

Copulation<\/span><\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Although all birds have internal fertilization, most do not have a penis; a penis is only present in waterfowl and the large flightless birds. Copulation may continue regularly and only stop when egg laying is over or may continue through incubation. In some species, copulation is necessary to stimulate nest-building and\/or incubation.<\/span><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0The entire process of courtship and reproduction is complex, with external stimuli and hormones interacting to produce a sequence of events from copulation to incubation. Most often the external stimulus is the lengthening period of daylight. A less passive influence is exemplified by the Red-billed Quelea of Africa which starts to breed when green grass emerges after a heavy rainfall.<\/span><\/p>\n