Patterns of parent-absent begging in nestling European starlings (Sturnus vulgaris)

Abstract

Parent-offspring communication mediates feeding rates through begging by nestlings, which is energetically expensive and may alert predators to the nest’s location, but benefits the nestlings by increasing body condition. Parent-absent begging is a behaviour that has the same risks as parent-present begging, but lacks the immediate benefits. This behaviour is prevalent in many passerine bird species, including European starlings (Sturnus vulgaris). During the European starling’s annual breeding season (May-July) I recorded nestling begging vocalizations at 18 broods located on the campus of Saint Mary’s University, Halifax, N.S., Canada, to examine parent-absent begging. Nestling vocalizations were recorded on days two, seven, 12, 17 and the day before fledging to monitor changes over the nestling period. I predicted that parent-absent begging would increase in European starling nestlings throughout the nestling period, because multiple studies on cavity-nesting species have found that parent-absent begging increases with age. Recordings were analyzed using Syrinx sound analysis software examining the first seven parent-absent intervals occuring after 10:00 am. It was found that there were significant differences in percentage of time spent begging in the absence of parents across the nestling period with it increasing from Days two to Day 17 followed by a decrease in parent-absent begging on the day before fledging. When examining the earlier and later broods separately there were no significant differences found. This study has implications in understanding avian behaviour and will provide insight to the nature of begging, and should guide future studies on European starlings and parent-offspring communication and Saint Mary’s University.