Azure-winged MagpiesCyanopica cyanustrade off reproductive success and parental care by establishing a size hierarchy among nestlings

Autor: Xin-Wei Da, Juan-Juan Luo, Li-Li Xian, Li-Fang Gao, Bo Du
Rok vydání: 2018
Předmět:
Zdroj: Ibis. 160:769-778
ISSN: 0019-1019
DOI: 10.1111/ibi.12575
Popis: It is common in birds that the sizes of nestlings vary greatly when multiple young are produced in one nest. However, the methods used by parents to establish size hierarchy among nestlings and their effect on parental provisioning pattern may differ between species. In the Azure-winged Magpie Cyanopica cyanus, we explored how and why parents controlled the sizes of nestlings. Asynchronous hatching was the main cause of size hierarchy within the brood, although the laying of larger eggs later in the laying sequence reduced this effect. Parents with asynchronous broods produced more eggs and fledged more nestlings than those with synchronous broods but their brood provisioning rates, food delivery per feeding bout and feeding efficiency did not differ. We performed a cross-fostering experiment to synchronize some asynchronous broods. Provisioning rates of asynchronous broods were lower than those of synchronized broods, but the daily growth rates and fledging body mass of their nestlings were not different. Our findings indicate that parents of asynchronous broods can achieve higher reproductive success than those of synchronous broods based on the same parental care, and the same reproductive success as those of synchronized broods based on less parental care. It appears that parent birds can better trade off reproductive success and parental care by establishing a size hierarchy among nestlings.
Databáze: OpenAIRE
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