To Share or Not to Share: Food Sharing in Wild Azure-Winged Magpie (Cyanopica cyanus)

Food sharing is very common in the animal kingdom. Despite extensive research, the mechanisms underlying food sharing remain debated. Moreover, the majority of studies on food sharing in non-human animals have been conducted under controlled environments. The natural behavioral characteristics and ecological factors influencing the natural selection of food sharing are still not well understood. In this study, we introduce a method to examine food-sharing behaviors in wild birds within their natural habitat. Using two types of feeders-one permitting food sharing with conspecifics and the other providing exclusive access to food-along with infrared cameras to record feeder-triggering events, we found that azure-winged magpies did not exhibit proactive food-sharing behaviors. However, they did exhibit passive food-sharing behaviors under conditions of low food availability. Consistent with the harassment-avoidance hypothesis, the birds prioritized the sharing feeders to decrease harassment from food snatching when food was limited. These findings suggest that food sharing is likely shaped into a passive behavioral pattern under limited resources conditions, which induce conflicts within social groups. This context-dependent strategy may effectively reduce harassment costs, optimize individual access to resources to maximize individual benefits, and potentially enhance the survival of other group members.