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| The population of Little Owls in Denmark is close to extinction. The main cause is food
limitation during the breeding season. Efforts to improve breeding success include providing
breeding pairs with supplementary food and attempts to improve foraging habitats
by creating short grass areas near the nests. In addition to increasing the reproductive output,
feeding and habitatmanagementmay cause parents towork less hard improving their
future reproductive value. We studied working efforts of five radio-tagged Little Owl
pairs in years of absence and presence of food provisioning, and/or access to short sward
vegetation areas near to the nest.We quantifiedmovement as theminimumflight distance
hour–1 (MFD), using themean distance from the nest (DN) as a supplementary index. Under
unmanipulated conditions, males had higherMFD and DN than females. If provided
with food and/or areas with short sward vegetation, males but not females reduced their
MFD and DN significantly. If MFD was adjusted for DN (the two measures correlated
positively), both sexes reduced their DN-adjusted MFD as response to food provisioning
but not to habitat provisioning. Food provisioning therefore had similar proximate effects
on the foraging effort ofmales and females, whereas provisioning of short sward habitats
had an indirect effect onmale but not female MFD, because of decreased commuting distances
between nest and foraging sites. The results indicate that food provisioning not
only leads to increased reproductive output in an endangered raptor, but also to decreased
working effort, which in turn may improve adult survival. | |
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