Kouba Marek, Bartoš Luděk, Št'astný Karel
Czech University of Life Sciences Prague, Faculty of Environmental Sciences, Department of Ecology, Praha 6- Suchdol, Czech Republic.
Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Animal Science and Ethology, Praha 6- Suchdol, Czech Republic; Institute of Animal Science, Department of Ethology, Praha 10- Uhříněves, Czech Republic.
PLoS One. 2014 Apr 23;9(4):e95594. doi: 10.1371/journal.pone.0095594. eCollection 2014.
Begging behaviour of nestlings has been intensively studied for several decades as a key component of parent-offspring conflict. There are essentially two main theories to account for intensity of food solicitation among offspring: that intensity of begging is related to some form of scramble competition between nest mates or that it offers honest signalling of need to parents. The vast majority of studies which have addressed begging behaviour have been based on observations of, and experiments on, nestlings and have not considered begging behaviour, during the post-fledging period. Begging vocalizations in this post-fledging phase of dependence have rarely been studied, despite the importance of vocalizations as a communication method between offspring and parents, particularly for nocturnal species. We radiotracked 39 fledglings of the Tengmalm's owl (Aegolius funereus) in two years with different availability of prey: 2010 (n = 29 fledglings) and 2011 (n = 10 fledglings) and made 1320 nightly localizations in which we recorded presence or absence of begging calls. Within years, the most important measures related to the probability of vocalization were body condition at fledging, time of night, number of surviving siblings, age and weather conditions. Begging intensity increased with age in both years; however, in the year with low prey availability fledglings vocalized significantly more often. The main factor causing these differences between years was probably the different availability of prey, affecting breeding success, post-fledging behaviour, and thus also both short- and long-term needs of offspring. We believe that our results suggest honest signalling of their fledgling's need.
几十年来，雏鸟的乞食行为作为亲代与子代冲突的关键组成部分，一直受到深入研究。关于后代食物索取强度，基本上有两种主要理论：乞食强度与巢内同伴之间某种形式的争夺竞争有关，或者它向父母诚实地表明需求。绝大多数关于乞食行为的研究都是基于对雏鸟的观察和实验，并未考虑雏鸟离巢后的乞食行为。尽管发声作为后代与父母之间的一种交流方式很重要，尤其是对于夜行性物种，但在雏鸟离巢后的依赖阶段，乞食叫声很少被研究。我们在两年内对39只长尾林鸮（Aegolius funereus）雏鸟进行了无线电追踪，这两年猎物的可获得性不同：2010年（n = 29只雏鸟）和2011年（n = 10只雏鸟），并进行了1320次夜间定位，记录了乞食叫声的有无。在同一年里，与发声概率相关的最重要指标是离巢时的身体状况、夜间时间、存活兄弟姐妹的数量、年龄和天气状况。在这两年中，乞食强度都随年龄增加；然而，在猎物可获得性低的年份，雏鸟发声的频率明显更高。导致年份之间出现这些差异的主要因素可能是猎物可获得性不同，这影响了繁殖成功率、雏鸟离巢后的行为，进而也影响了后代的短期和长期需求。我们认为，我们的结果表明雏鸟诚实地表明了它们的需求。
