Parent-offspring interactions in a long-lived seabird, the Little Auk (Alle alle): begging and provisioning under simulated stress

Abstract

Long-lived seabirds are good models to study the mechanisms that mediate the parent-offspring interactions. Contrary to studies under natural conditions, experimental manipulations allow us to assess the birds' reactions in a short time period. We used the stress hormone corticosterone as an independent experimental factor to simulate the stress reaction, to examine changes in the behaviour of Little Auk chicks and parent birds. In the first experiment, we hypothesised that after enhancement of the corticosterone level Little Auk (Alle alle) chicks intensify their begging performance and attain a higher pre-fledging body mass than the control chicks. In the second experiment, we hypothesized that parent Little Auks with an increased corticosterone level feed their chicks less frequently and spend less time at the colony than their untreated partners and the control birds. We also expected that chicks with one parent implanted with corticosterone fledge later and with a lower body mass than chicks of two untreated parents. The obtained results supported the above hypotheses. We demonstrated that modification of begging performance in Little Auks constitutes an adaptive mechanism that guards against the decrease in the chicks' body condition during stressful periods. Even though the provisioning rate in Little Auks can be regulated according to the chick's needs (expressed by the intensity of the begging display), it appears that adult birds regulate their provisioning strategy primarily according to their body state. The results suggest that parent Little Auks under stressful conditions will decrease their parental effort and redirect the available energy towards self-maintenance. The study provides novel insights into the behaviour of long-lived alcids using an experimental approach on free-living birds.

Aversive Foraging Conditions Modulate Downstream Social Food Sharing

“…An inhibition of trophallaxis with younger nurse bees under threatening conditions aligns with the phenomenon in which some species of birds decrease their parental provisioning to redirect energy towards self-maintenance in stressful conditions 32,33 . On the evolutionary scale, unpredictable and poor environments lead to parents paying less attention to chicks’ begging and instead using cues such as body size to determine provisioning 34 .…”

The Little Auk Alle alle: an ecological indicator of a changing Arctic and a model organism

“…Since the costs of foraging are considerable (Gabrielsen et al 1991;Konarzewski et al 1993), parent birds should also be resistant to chick begging, so potentially, the evolution of parent-offspring communication could be constrained. Nevertheless, Little Auk parents do communicate with their chicks acoustically (Kidawa et al 2017), and potentially in other ways, too. The contrasting expectation and results create an intriguing background for examining the issue of parent-offspring communication.…”

Duration of female parental care and their survival in the little auk Alle alle - are these two traits linked?

“…A study on little auk parents with experimentally increased flight costs during the chick-rearing period revealed that they are able to increase parental effort to some extent (Harding et al 2009). Also, it has been revealed that artificially increased chick-begging intensity (by the exogenous corticosterone administration) induced a higher feeding frequency by little auk parents (Kidawa et al 2017). An extension of parental effort, however, may affect parents' survival.…”