Abstract

Evolutionary theory predicts that when intrasexual competition is intense, risky behaviors can evolve if they enhance reproductive success. Here we tested the idea that polygynous males exhibit predictable variation in risk-taking during intense competition for mates. We conducted an observational study of a village weaverbird (Ploceus cucullatus) breeding colony, and video recorded synchronous fleeing events, a common predator avoidance behavior. Males adjusted their flight from the colony according to the amplitude (loudness) and Wiener entropy (harshness) of conspecific alarm calls during a perceived threat. Males also varied in how often they fled the colony. Specifically, in line with predictions based on the value of a male’s territory, males with more nesting females were less likely to flee, and returned sooner if they did flee, compared to males with fewer nesting females. Males with a nest under construction also returned to their nests sooner than males without constructions in progress, consistent with predictions based on nest sabotage by conspecifics. These results suggest that male weavers perform a cost-benefit analysis in real time in order to decide how to respond to a perceived threat, with self-protection trading off with the security of one’s territory and mates.

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