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Seasonal breeder
Seasonal breeders are animal species that successfully mate only during certain times of the year. These times of year allow for the births at a time optimal for the survival of the young in terms of factors such as ambient temperature, food and water availability, and even changes in the predation behaviors of other species. Related sexual interest and behaviors are expressed and accepted only during this period. Female seasonal breeders will have one or more estrus cycles only when she is "in season" or fertile and receptive to mating. At other times of the year, they will be anestrus. Unlike reproductive cyclicity, seasonality is described in both males and females. Male seasonal breeders may exhibit changes in testosterone levels, testes weight, and fertility depending on the time of year.
Seasonal breeders are distinct from opportunistic breeders, which mate whenever the conditions of their environment become favorable, and continuous breeders like humans that mate year-round.
==Breeding season==
The breeding season is the most suitable season, usually with favourable conditions and abundant food and water, for breeding. Abiotic factors such as the timing of seasonal rains and winds can also play an important role in breeding onset and success.
Many species breed in colonies or large communities which is known as communal breeding. It is common to see large congregations of these species in particular favourable locations in their breeding seasons. These breeding colonies and their location are generally protected by wildlife conservation laws to keep the species from going extinct. Some species have evolved for communal breeding in large breeding colonies and can not breed in smaller numbers or pairs alone. These species can be threatened by imminent extinction if they are hunted on their breeding grounds or if their breeding colonies are destroyed. The Passenger pigeon is a famous example of probably the most numerous land bird on the American continent which had evolved for communal breeding that went extinct due to large scale hunting in its communal breeding grounds during the breeding season and its inability to breed in smaller numbers.〔Jerram L. Brown, 1978〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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