Krebs EA, Cunningham RB, Donnelly CF
Division of Botany and Zoology and \|P%Statistical Consulting Unit of the Graduate School, The Australian National University, Canberra
Anim Behav. 1999 Apr;57(4):753-763. doi: 10.1006/anbe.1998.1029.
In birds, asynchronous hatching typically leads to lower growth and survival of last-hatched chicks. However, all crimson rosella Platycercus elegans, chicks grow at the same rate, although first-hatched chicks can be as much as seven times heavier than last-hatched chicks at the end of hatching. We examined the delivery and distribution of food to 18 rosella broods by videotaping feeds and simultaneously recording mass changes in the nestbox using a digital balance. Parents visited the nest infrequently and delivered loads of up to 25% of their body weight during a feeding visit. Male rosellas consistently delivered larger loads and consequently had higher feeding rates (g/h) than females. Parents distributed food between chicks by direct regurgitation in a series of up to 51 food transfers. Overall, chicks of all hatching ranks received equal numbers of transfers, but parents differed in how they distributed food within the brood. Males fed first-hatched chicks more than last-hatched chicks, whereas females distributed food equally to all chicks. Selective feeding of small chicks might be costly to females since they delivered food more slowly than males and spent more time in the nestbox. Thus female rosellas may invest more in current reproduction than males. Parents also distributed food differently to male and female chicks. Large males were fed more than all other nestlings, while female nestlings were fed equally irrespective of size. This study confirms that complex patterns of parental allocation occur in wild populations. Copyright 1999 The Association for the Study of Animal Behaviour.
在鸟类中，异步孵化通常会导致最后孵化出的雏鸟生长缓慢且存活率较低。然而，对于所有绯红玫瑰鹦鹉（Platycercus elegans）雏鸟来说，它们的生长速度相同，尽管在孵化结束时，先孵化出的雏鸟体重可能比最后孵化出的雏鸟重多达七倍。我们通过拍摄喂食过程并同时使用数字天平记录巢箱内雏鸟体重变化，研究了18窝玫瑰鹦鹉雏鸟的食物供应和分配情况。亲鸟很少光顾巢穴，每次喂食时所运送的食物量高达它们体重的25%。雄性玫瑰鹦鹉运送的食物量始终更大，因此其喂食速率（克/小时）比雌性更高。亲鸟通过直接反刍的方式在雏鸟间分配食物，一系列喂食过程中最多有51次食物传递。总体而言，所有孵化顺序的雏鸟接受的食物传递次数相同，但亲鸟在巢内分配食物的方式有所不同。雄性亲鸟喂食先孵化出的雏鸟多于最后孵化出的雏鸟，而雌性亲鸟则将食物平均分配给所有雏鸟。对体型较小的雏鸟进行选择性喂食对雌性亲鸟来说可能代价高昂，因为它们运送食物的速度比雄性慢，且在巢箱内花费的时间更多。因此，雌性玫瑰鹦鹉可能比雄性在当前繁殖中投入更多。亲鸟给雄性和雌性雏鸟分配食物的方式也不同。体型较大的雄性雏鸟比其他所有雏鸟得到的食物更多，但雌性雏鸟无论体型大小都被平等喂食。本研究证实，野生种群中存在复杂的亲代分配模式。版权所有1999年动物行为研究协会。
