Doi: https://doi.org/10.13157/arla.72.2.2025.sc5
Authors: Juan MORENO
E-mail: jmoreno.jmk@gmail.com
Published: Volume 72.2, July 2025. Pages 329-337.
Language: English
Keywords: breeding date, ectoparasites, nest disturbance, nestling handling and premature fledging.
Summary:
It has been proposed that nestling manipulation by researchers or bird ringers may precipitate fledging. Premature fledging of broods may have deleterious effects on fledgling survival due to their limited flying ability during their first days out of the nest, during which drastic falls in offspring survival have been observed. Thus it is important to ascertain whether early fledging may be an unwelcome outcome of standard ringing and measurement procedures. This was tested by field experiment during two breeding seasons on a Spanish population of nest-box breeding pied flycatchers Ficedula hypoleuca. Three levels of disturbance were randomly assigned to nests: 1) maximum disturbance, where nestlings were ringed at seven days old and measured and weighed at 13 days old, and nest-boxes were opened daily to ascertain nestling presence from day 15 until the whole brood fledged; 2) medium disturbance, with similar handling and measurement procedures but without nest-box checks after day 15, and 3) minor disturbance, where nestlings were ringed on day seven but were not handled after that age and no nest-box checks were conducted after day 15. whole-brood fledging age, (at 18 days on average), for the two reduced disturbance treatments was ascertained through daily observation of parental activity near the nest-box, with subsequent checks of nest-boxes when no activity was detected. No effect of disturbance on fledging age was found, controlling for year. The only factors clearly linked to early fledging were hatching date (late broods fledged at earlier ages) and the presence of ectoparasitic mites Dermanyssu gallinae (infested broods fledged earlier). No significant harmful effects of standard nestling manipulation or nest-check procedures were thus detected.
