作者: Markku Orell , Seppo Rytkönen , Kari Koivula
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摘要: . Divorce rates were measured in a population of willow tits, which the size some broods was manipulated. The population, with annual survival ca 63 and 64% for females males, respectively, had relatively low divorce rate 12·0%. experiments on altered breeding success did not support hypothesis that poor is likely to initiate divorce. Most variation reproductive pairs differing history attributable age female, yearling being least successful. Yearling birds split up more often than older birds. Divorced usually paired older, divorced males younger, mates their previous ones. With new mate, bred successfully advanced laying date widowed indicating beneficial. even remained unpaired season after splitting up. thus seems be strategy chosen by increase future success. decision initiated when female can obtain higher-ranked mate among her own or neighbouring winter flock.