Effect of nest-site microclimatic conditions on nesting success in the Lesser Kestrel (Falco naumanni)

Orli Bobek
Adiv Gal
David Saltz
Uzi Motro

Capsule: Microclimatic conditions in the nest of the Lesser Kestrel (Falco naumanni), particularly the percentage of time of extremely low humidity, affect breeding success.Aim: (1) To study the effect of within-nest temperature and humidity on nest productivity, and the correlation between nest productivity and the order of dates on which nests were occupied by the parents. (2) To compare microclimatic conditions in the nest, breeding success and order of occupation between nests under tile roofs and artificial nest boxes.Methods: Three different Lesser Kestrel colonies in Israel – one rural, one urban and one in an open country habitat. Data loggers, that measure temperature and humidity, were put in 39 nests for the entire breeding period. The number of fledglings was recorded for each nest, as well as the date of occupation.Results: (1) Full microclimatic data from 35 nests suggest that percentage of time of extremely low humidity is the major predictor of nest productivity. (2) The urban colony had the lowest breeding success of the three colonies. (3) Sites of more successful nests were occupied earlier. (4) No significant difference in mean productivity between nests in roofs and nest boxes, but nests in roofs were occupied earlier.Conclusion: Nest microclimate affects nesting success in addition to colony location.

July, 2018