Growth patterns of Common Kestrel (Falco tinnunculus) nestlings: effects of hatching order, brood size and habitat factors
Description
Birds of prey are important for their regulatory roles in ecosystems and as indicators of environmental health. Many conservation programs have been implemented to support their populations, including the provision of artificial nest boxes. The Common Kestrel (Falco tinnunculus) readily accepts such nest sites and may even prefer them when available. In this study, we examined the combined effects of habitat characteristics and biological factors on nestling growth. Brood size, hatching order, and breeding phenology significantly influenced growth rates of the tarsus and head. Nestlings in broods of four showed the lowest growth increments, whereas those in larger broods exhibited higher values. In the largest broods, the fifth and sixth nestlings grew faster than their older siblings. Tarsus and head growth rates were also positively correlated with the date of the first egg. In contrast, habitat characteristics had no measurable effect on growth rates. Our findings highlight the relevance of nestling growth parameters as indicators of breeding performance and may support the effectiveness of Kestrel conservation programs in rural landscapes. We recommend incorporating chick growth rates as a valuable biological parameter in the evaluation of raptor conservation efforts.
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Institutions
- Uniwersytet Przyrodniczo Humanistyczny w Siedlcach