Patterns of parent-absent begging in European Starling (Sturnus vulgaris) nestlings

Parent–offspring communication mediates parental provisioning rates through nestling begging. Although begging can be energetically costly and it potentially attracts predators to the nest, it is critical to nestling survival. Parent-absent begging is a behavior that has similar costs as parent-present begging but lacks the immediate benefits and yet occurs among several passerine species. We recorded European Starling (Sturnus vulgaris) nestling begging vocalizations at 18 nest boxes on days 2, 7, 12, 17 of the nestling period and the day before fledging to examine whether parent-absent begging occurred, and if so, whether the frequency of parent-absent begging changed with nestling age. We predicted that, like other cavity-nesting species, European Starling nestlings would spend more time begging in the absence of parents as they aged. We found that the average proportion of time nestlings spent parent-absent begging increased significantly from days 2 and 7 to days 12 and 17, then declined significantly on the day prior to fledging. Offspring provisioning rates remained high on the day before fledging, when growth rates have slowed, and did not differ significantly from the early and middle stages of the nestling period. Parent-absent begging may function in advertising hunger.