Catry P, Ratcliffe N, Furness RW
Applied Ornithology Unit, IBLS, University of Glasgow
Anim Behav. 1997 Dec;54(6):1475-1482. doi: 10.1006/anbe.1997.0552.
There are two main theories attempting to explain divorce in birds as an adaptive decision for at least one of the members of the pair. The 'incompatibility hypothesis' states that birds separate because they are unsuccessful breeders as a pair, although their individual characteristics are not negative per se. Divorce comes about as an initiative of both individuals to search for a more compatible mate. The 'better option hypothesis' suggests that divorce is usually initiated by one of the birds in search of a 'higher quality' partner (or territory). The ages of partners of great skuas, Catharacta skuabreeding on Foula (Shetland) were poorly correlated (r48=0.28), 22% of the partners differing in age by 10 years or more. Mate fidelity in this population was high, with an annual divorce rate of only 6.4% (N=20/311). Death was responsible for three times more interruptions of partnerships than divorces. Three types of divorce were detected. (1) In six cases, females deserted their partners, leaving them temporarily unpaired. (2) One female was recorded being forced to desert her partner by a usurper. (3) One female deserted her partner after they lost their breeding territory to another pair. Mate changes had a direct cost, because new pairs (of experienced birds) laid later in the season and reared fewer chicks. After mate loss, 26% (N=61) of the individuals did not breed, while faithful pairs always laid eggs (N=222). Males, but not females, had a higher probability of remaining unpaired after being divorced than after becoming widowers. There was no difference between the sexes in the probability of re-pairing after a mate died. The results suggest that divorces that are initiated by birds within the pair are better explained by the 'better option hypothesis' than the 'incompatibility hypothesis'.Copyright 1997 The Association for the Study of Animal Behaviour
有两种主要理论试图将鸟类的离婚现象解释为配偶双方中至少一方的适应性决策。“不相容假说”认为，鸟类分开是因为它们作为配偶繁殖不成功，尽管它们各自的特征本身并非负面。离婚是双方主动寻找更合适配偶的结果。“更好选择假说”则表明，离婚通常是由其中一只鸟发起，以寻找“更高质量”的伴侣（或领地）。在福拉岛（设得兰群岛）繁殖的大贼鸥（Catharacta skua）配偶年龄相关性很差（r48 = 0.28），22%的配偶年龄相差10岁或更多。该种群中的配偶忠诚度很高，年离婚率仅为6.4%（N = 20/311）。死亡导致的伴侣关系中断次数是离婚的三倍。检测到三种类型的离婚情况。（1）在六个案例中，雌鸟抛弃了它们的伴侣，使其暂时处于无配偶状态。（2）记录到一只雌鸟被一只侵入者迫使抛弃其伴侣。（3）一只雌鸟在它们的繁殖领地被另一对鸟占据后抛弃了其伴侣。更换配偶有直接成本，因为新的配偶对（经验丰富的鸟）在季节后期产卵，育雏数量较少。配偶丧失后，26%（N = 61）的个体没有繁殖，而忠诚的配偶对总是产卵（N = 222）。离婚后雄性比丧偶后保持单身的可能性更高，而雌性则不然。配偶死亡后重新配对的概率在两性之间没有差异。结果表明，配偶双方中鸟类主动发起的离婚用“更好选择假说”比“不相容假说”能得到更好的解释。版权所有1997动物行为研究协会
