Aerial insect-hunting by hobbies falco subbuteo in relation to weather

Abstract

The relationship between weather and aerial insect-hunting by Hobbies was studied at a site in the New Forest in 1984 and 1985, during the pre-incubation period. Insect-hunting was restricted to the warmest part of each day and was not observed below 13°C. This suggests that there is a temperature threshold below which Hobbies do not attempt to hunt for insects. The existence of this threshold is further indicated by the behaviour of individual males in each year of the study. The rate at which the Hobbies struck insects was positively correlated with air temperature. It was also negatively correlated with wind speed but largely because wind speed was negatively correlated with temperature. Flying methods were related to weather in that the birds tended to use powered flight more as the air temperature fell. The energetics and-profitability of aerial insect-hunting are discussed. © Taylor& Francis Group, LLC.