The relationship between weather and reproduction of the Barn Owl Tyto alba in a semi-arid agricultural landscape in Israel

Even though the Barn Owl (Tyto alba) is distributed worldwide, little information is available on how weather affects Barn Owl breeding outside of Europe and North America. For instance, if cold temperatures can negatively influence population dynamics in temperate regions, heat could have a similar negative effect in arid regions. We have studied a breeding population of Barn Owls in a semi-arid agricultural environment over 13 years in Israel in order to determine whether lack of rain and hot ambient temperatures impair Barn Owl reproductive success. The percentage of nest boxes occupied by Barn Owls was not related to any of the weather variables, whereas the number of nestlings per Barn Owl pair and the percentage of pairs that succeeded to fledge young was lower in years when it started to rain later in the season and when the minimum daily temperature was higher during the breeding season. In comparison to temperate regions, heat is detrimental to Barn Owl breeding and early precipitation is probably important in boosting vegetation and, in turn, the abundance of small mammals, the Barn Owl's staple food.