Barn Owl ( Tyto alba ) breeding biology in relation to breeding season climate

Chausson, Alexandre ; Henry, Isabelle ; Almasi, Bettina ; Roulin, Alexandre

In: Journal of Ornithology, 2014, vol. 155, no. 1, p. 273-281

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    Winter weather has a strong influence on Barn Owl (Tyto alba) breeding biology. Here, we analyzed the impacts of weather conditions on reproductive performance during the breeding season using data collected over 22years in a Swiss Barn Owl population. Variations in rain and temperature during the breeding season played an important role in within-year variation in Barn Owl reproduction. An increase in rainfall during the period from 4 to 2weeks preceding egg laying had a positive effect on clutch size. In contrast, fledgling body mass was negatively influenced by rainfall during the 24h preceding the measurements. Finally, ambient temperature during the rearing period was positively associated with brood size at fledging. In conclusion, weather conditions during the breeding season place constraints on Barn Owl reproduction.