Parental Care and the Transition To Independent Feeding in the Young Spotted Flycatcher (Muscicapa Striata)

• Published in: Behaviour 1976, Vol.59 (3-4), p.280-294
• Main Author: Davies, N.B
• Format: Article
• Language: English
• Subjects: Bird nesting; Birds; Energy intake; Flycatchers; Food; Food intake; Parents; Predators; Songbirds; Travel time
• ISSN: 0005-7959; 1568-539X
• DOI: 10.1163/156853976X00415

1. In most passerine birds there is a period of parental care after the young leave the nest. The behaviour of wild young Spotted Flycatchers, Muscicapa striata, and interactions with their parents was studied in an attempt to answer the question "When should the young become independent?" The young flycatcher was regarded as predator with two feeding strategies, namely begging for food off the parents and attempting to capture prey (flying insects) itself. 2. The young left the nest when only half grown. As they got older there was a change from self feeding when satiated to self feeding when hungry, a decrease in the rate of pecking at inedible objects and an increase in the complexity and rate of capture techniques employed. Improvement in feeding performance was probably mainly due to continued growth and the parents did not play any part in these changes. 3. The initiative for parental feeding passed from the parents in the early stages to the young later on. As the young got older, the parents became more reluctant to feed them as reflected in the increased rate of chasing after the parents by the young and the increase in the proportion of these chases which resulted in no food. The parents brought large prey to the young when the time taken to take the prey to the young (travel time) was large and only took small prey when the travel time was small. 4. The energy gain per unit effort of begging decreased with age while that for self feeding increased. At 15-16 days after leaving the nest, self feeding became more profitable than begging. At this time the young suddenly increased their rate of capture attempts so that the energy intake by self feeding increased from 30% to 80%. One to two days later the young stopped begging altogether and became independent. It is suggested that the young can assess the profitability of their two feeding strategies and become independent of their parents when the profitability of self feeding exceeds that of begging. /// 1. Bei den meisten Kleinvogelarten werden die Jungen nach dem Ausfliegen noch eine Zeitlang von ihren Eltern gefüttert. Das Verhalten von flüggen Jungen des Grauschnäppers, Muscicapa striata, und die Wechselbeziehungen zu ihren Eltern wurden im Freiland untersucht um abzuklären, zu welchem Zeitpunkt die Jungen von ihren Eltern unabhängig werden sollten. Die jungen Grauschnäpper können zwischen zwei Nahrungserwerbsmöglichkeiten wählen; sie können ihr Futter durch Betteln von ihren Eltern erhalten, o