0000000000312373
AUTHOR
Beat Naef-daenzer
The design of artificial nestboxes for the study of secondary hole-nesting birds: A review of methodological inconsistencies and potential biases
The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines. Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents. However, when comparing results across study sites the use of nestboxes may also introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. However, the use of …
Sex-biased survival of nestlings under unfavourable conditions drives secondary sex ratio in little owls (Athene noctua)
Identifying variation in key life history traits is crucial to predict population dynamics of endangered species. An increased bias in sex ratio as a result of low habitat quality can reinforce population decline and drive small populations to extinction. This is particularly true for monogamous bird species such as the little owl (Athene noctua). However, the underlying mechanisms driving biased sex ratios often remain elusive. Using a robust sample of molecular sex determination data recorded at two nest visits within each of 247 broods we examined the development in brood sex ratio, sexual size dimorphism and factors affecting the survival of little owl nestlings. Brood sex ratio in litt…