Parental Coordination of Chick Provisioning in a Planktivorous Arctic Seabird Under Divergent Conditions on Foraging Grounds

Abstract

An increasing number of studies report coordinated chick provisioning by avian parents. Although the pattern of parental coordination varies across species, broad occurrence of this coordination suggests that it has an adaptive value: it may increase individual fitness via higher offspring survival, faster offspring growth rate and/or higher body reserves of the parents. However, to what extent the pattern of coordinated provisioning in a species represents a flexible response to current foraging conditions remains an open question. Here, we examined coordination of chick provisioning in the Little Auk (Alle alle), a planktivorous seabird species that breeds in the Arctic. Harsh environmental conditions impose bi-parental care on this species, and high variability within and across breeding seasons promotes flexibility in parental involvement to secure breeding success. During the chick rearing period, parents exhibit a dual-foraging strategy (i.e., alternating long foraging trips, serving to maintain the adults' body reserves, with several short trips aimed to provision the chick). We examined coordination of parental provisioning across five breeding seasons varying in terms of environmental conditions and found that the parents indeed coordinate their provisioning, avoiding performing long trips simultaneously and thus enabling a more even distribution of feeding through time. We also examined chick body condition in relation to the level of parental coordination to test the potential adaptive value of coordination, but we found no significant relationship between these two parameters. We found high variability in the level of the coordination between pairs, and this variability was similar across all study seasons, which represented a wide range of experienced environmental conditions. Nevertheless, we found that the energy density of food loads delivered to chicks was associated with the level of parental coordination: when conditions were characterized by the delivery of higher-energy food loads, the level of coordination exhibited by the studied population was higher. These findings suggest that environmental conditions somehow affect parental coordination, but the range of the environmental variation could be still below a critical threshold of extreme conditions that would trigger more pronounced modifications of parental foraging patterns and coordination.

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

“…securing even in time food delivery; Wojczulanis- Jakubas et al 2018). Parental coordination has been found to be highly variable and could not be explained by environmental conditions (Grissot et al 2019). In such a context, female brood desertion in the little auk could be linked to low coordination.…”

“…During observations, we continuously observed focal individuals and noted their presence in the colony every 10 min. We recorded all events of chick-feeding [bird appears after a period of absence in the colony, and enters the nest with a gular pouch filled with food; see more details on the observation routine in (Wojczulanis-Jakubas and Jakubas 2012; Grissot et al 2019)]. For automatic recording of colony attendance of birds and chick feeding frequency, we set video cameras (four types, commercial HD models, with 1-s time lapse mode) at each focal nest.…”

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

“…Currently, parental care is being intensively studied in the context of cooperation between the breeding partners (Griffith 2019; Wojczulanis-Jakubas 2021), where the Little Auk has been found to be a particularly useful model species (Wojczulanis-Jakubas et al 2018a). Recent results have demonstrated that Little Auk parents not only both provide food for their chick at an equal rate, but also coordinate their foraging trips so as to minimize the time between feedings (Wojczulanis-Jakubas et al 2018a;Grissot et al 2019).…”

“…Studies show that parenting males and females avoid overlapping their long foraging trips, i.e. coordinate their foraging flights, thereby ensuring regular provisioning of the chick (Wojczulanis-Jakubas et al 2018a;Grissot et al 2019).…”

Limited plasticity in gene expression for providing or receiving parental care under different temperatures

“…In some cases, this plasticity may be immediately detectable as a change in behavior. For example, many birds compensate for harsh breeding season conditions by increasing the density of food loads delivered to chicks (Grissot et al 2019) or by extending incubation times (McClintock et al 2014;Sharpe et al 2021), while offspring have been shown to upregulate metabolic and immune pathways in response to the removal of a caring parent (Ziadie et al 2019;Körner et al 2020;Mashoodh et al 2021) or exposure to pathogens (Körner et al 2020). However, when parents and offspring are pushed to their physiological limits, maintaining a stable phenotype is likely just as important for ensuring offspring success as is altering behavior.…”