Sanz Juan José
Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (CSIC), José Gutierrez Abascal 2, E-28006 Madrid, Spain e-mail:
Oecologia. 1999 Nov;121(3):377-382. doi: 10.1007/s004420050942.
Post-nuptial moult and reproductive success were studied in relation to timing of breeding in blue tits, Parus caeruleus, breeding in southern Europe. A group of experimentally delayed pairs was created by removing first clutches, thereby inducing late repeat clutches. Reproductive success and post-nuptial moult of delayed pairs were compared with both control pairs that bred early and unmanipulated late-breeding pairs. Delayed pairs fledged fewer young and with a lower body mass than control pairs. However, the number of fledged young and fledgling mass did not differ between delayed and late-breeding pairs. These results were more consistent with the date hypothesis, and it is concluded that the timing of breeding and reproductive success may be causally related in the blue tit. This study reveals a harmful effect of relaying on female body mass at the end of the nestling period. Therefore, females apparently pay the costs of relaying, since a reduction in body mass during the nestling period may be accompanied by a lowered survival probability. Delayed and late-breeding males often began moulting while still feeding young, but neither control males nor females from the three study groups did so. These results support the view that timing-related energy constraints on breeding may be important causes of a seasonal decline in reproductive success at different latitudes.
对在欧洲南部繁殖的蓝山雀（Parus caeruleus）的婚后换羽和繁殖成功率与繁殖时间的关系进行了研究。通过移除第一窝卵来创建一组实验性延迟配对，从而诱导晚些时候的重复窝卵。将延迟配对的繁殖成功率和婚后换羽情况与早期繁殖的对照配对以及未受操纵的晚期繁殖配对进行了比较。延迟配对育出的幼鸟数量比对照配对少，且幼鸟体重更低。然而，延迟配对和晚期繁殖配对育出的幼鸟数量和雏鸟体重并无差异。这些结果与日期假说更为一致，得出的结论是，蓝山雀的繁殖时间和繁殖成功率可能存在因果关系。这项研究揭示了重筑巢对雏鸟期结束时雌鸟体重的有害影响。因此，雌鸟显然要为重筑巢付出代价，因为雏鸟期体重的下降可能伴随着生存概率的降低。延迟配对和晚期繁殖的雄鸟常常在仍在喂养幼鸟时就开始换羽，但三个研究组中的对照雄鸟和雌鸟均未如此。这些结果支持了这样一种观点，即与时间相关的繁殖能量限制可能是不同纬度地区繁殖成功率季节性下降的重要原因。
