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Starling mothers, but not fathers, respond with a higher investment to parent-absent calls performed by nestlings

Begging behaviour in birds comprises a wide group of signals performed by nestlings to obtain feedings from their parents when they arrive at the nest. These signals are used by parents to obtain information about the general state and necessities of their offspring. This will eventually determine food allocation and parental investment. Besides this kind of signals, nestlings of some species also perform another kind of calls during parental absence. Some recent studies in the barn owl (Titto alba) have proposed a sibling-sibling interaction linked to these parent-absent signals, that seem to be highly determined by hunger state and related to the intention to compete for the next piece of food.

The fact that these calls are so conspicuous (they can be heard from many meters away from the nest) and frequent raises many questions. Why calling if nobody is listening to you? In this study we focused on whether parents could be perceiving these signals and responding to them, even if they are not with their chicks when they call?

To answer this, we carried out a playback experiment in the European starling (Sturnus unicolor), in a colony breeding in nestboxes. In this experiment we compared the parental visit rate of both males and females in nests under control conditions (environmental background noise playback) and experimental conditions (parent-absent calls playback). Results showed that females visited their nests more often (40%) if absent repeated calls were performed, whereas we did not found any difference for males. These sex-dependent responses could be explained because starling females normally invest more than males in feeding the offspring. Thus we would expect them to keep a tighter level of adjustment to the necessities of their nestlings than males.

However, the most important result of this study is that parent-absent repeat calls do have a parent-offspring communication role in this species, being perceived as a signal of need by females. In natural conditions, females may hear the calls while they are foraging in the neighbourhood, or when they approach the nest with food.

Our results also give rise to new questions for future research lines, for instance those related to the different strategies of parental care followed by males and females, or to the way in which this parent-offspring communication channel coexists with the role of these in calls in sib-sib interactions. 



  • Starling chicks begging while an adult bird cleans the nest