Breeding Behavior, Nestling Growth, and Begging Behavior in the Plain Laughingthrush (Garrulax davidi): Implications for Parent–Offspring Conflict

SIMPLE SUMMARY: Food allocation among nestlings of altricial birds is crucial for understanding the evolution of parent–offspring conflicts within avian families. Empirical studies have yet to reach a consensus on whether parents or offspring determine the food distribution within the brood. In the case of the Plain Laughingthrush (Garrulax davidi), we explore the relationship between parental feeding strategies and nestling begging behaviors. Due to hatching asynchrony, larger nestlings often outcompete their smaller siblings for food, although they do not consistently exhibit higher begging intensity. Generally, nestlings with the highest begging intensity are more likely to be fed first, underscoring the importance of nestling begging in parental food allocation. However, if the initial food recipients are already satiated and do not immediately consume the food, parents reallocate it to other nestlings. This re-feeding tactic reduces the chance of early-hatched nestlings monopolizing food due to their larger size. Our research demonstrates that, while parental food allocation primarily depends on nestling begging intensity, the decision to re-feed hinges on whether the initial recipients promptly ingest the food. ABSTRACT: Investigation on food allocation among nestlings of altricial birds is crucial in understanding parent–offspring conflicts within avian families. However, there is no consensus in empirical studies regarding whether parents or offspring determine the food allocation pattern within a brood. In the Plain Laughingthrush (Garrulax davidi), we examine the relationship between parental feeding strategies and nestling begging behaviors. Due to hatching asynchrony, larger nestlings have a competitive advantage in food acquisition over their smaller brood-mates; nevertheless, if the initial food-receivers were already satiated and did not immediately consume the food, parents would retrieve the food and re-allocate it to another nestling. This re-feeding tactic employed by parents reduced the likelihood of early-hatched nestlings monopolizing the food solely due to their larger body size. Our findings indicate that parents primarily allocated food based on nestling begging intensity, while their re-feeding tactic is determined by whether the first food-receivers have consumed the food. To date, our research demonstrates that while parental food allocation primarily hinges on the begging intensity of the nestlings, the decision to re-feed is contingent upon whether the initial recipients of the food ingest it immediately.