Diel feeding strategy during breeding in male Barn Owls (Tyto alba)

Abstract

International audienceDuring reproduction, birds are confronted with two requirements: building up their energetic reserves during the activity period, and provisioning the nest. Storing reserves imposes a higher flight cost and a lower hunting efficiency. This conflict is accentuated in species such as the Barn Owl (Tyto alba), where the nest food supply is entirely taken in charge by the male during a long period (ca. 37 days). We tested the prediction that Barn Owl males were postponing their meal to the end of the night in order to fly with a low body mass. Nocturnal changes in body mass (i.e., estimates of feeding events) were monitored remotely on six freeranging Barn Owl pairs nesting in eastern France using an automated weighing system. Male Barn Owls were gaining the more weight at the end of the night, supporting the prediction that they make their biggest meal after the nest provisioning activities hunting period that is taking place at the beginning of the night

Pheomelanin-based colouration is correlated with indices of flying strategies in the Barn Owl

“…The latter interpretation is consistent with the finding that wing feathers are more deeply anchored in the featherbearing integument in darker-reddish birds in order to sustain intense flying activity when the stomach is full. Because a full stomach will increase the cost of flying (Durant et al 2013), and because feathers more deeply anchored inside the feather-bearing integument will stabilize the feathers against external forces (Homberger and de Silva 2000), we suggest that darker-reddish Barn Owls can sustain more intense flying activities and hence fly more often than paler owls when their stomach is full. Our observations have a number of life-history implications.…”

“…Flying methods may therefore differ between pale and dark Barn Owls; consequently, differently coloured owls may differ in how they adjust stomach content and how deeply the wing feathers are anchored in the ''feather-bearing integument'' to stabilize the feathers against external forces (Homberger and de Silva 2000). Indeed, Durant et al (2013) showed that breeding males adjust their stomach content to the foraging effort by avoiding eating when they have to sustain intense foraging activities in order to feed their brood. Therefore, if one colour morph is better able to sustain intense flying activities, this morph could fly with a heavier stomach content than the other morph.…”

Breeding limits foraging time: evidence of interrupted foraging response from body mass variation in a tropical environment

“…Moulting is largely restricted to the wet season and moulting birds may carry larger body reserves (Gosler ). Fluctuations in food availability peaks within the wet season due to inter‐annual variation in rainfall pattern may also cause birds to vary body reserves accordingly depending on individual strategies (Babbitt and Frederick , Durant et al ).…”

An assessment of the reproduction, predation, and nesting behavior of Sulawesi Masked-owl (Tyto rosenbergii) in oil palm plantation: A case study of West and Central Sulawesi, Indonesia

“…Video recordings from camera traps show that males carry prey to the nest box and then feed them to females. Furthermore, during the breeding season, males provide the bring prey to be given to females, which are laying eggs or incubating, with preys for feeding (Durant et al 2013;Datta 2019). However, they both hunt during the rearing period to meet their food needs (Taylor 1994).…”