Strategic choices of attack location allow predators to counter a collective prey defence

Predator-prey interactions can drive arms races of complex adaptation and response patterns. While collective behaviour is common as anti-predator behaviour and well understood mechanistically, little is known on predator strategies in the context of collective prey defences. Here, we investigated attack strategies of predatory birds confronted with an effective collective anti-predator behaviour employed by shoals of small freshwater fish (Poecilia sulphuraria). Analysing over 700 attacks revealed that predators face a trade-off: placing attacks in the shoal centre leads to a stronger prey response, which decreases attack frequency but increases chance for success. The causal relationship between attack location and prey-response plasticity was confirmed experimentally through simulated attacks. Predators adjusted their strategies with conspicuous species avoiding the centre, sacrificing optimal attack positions for lower prey responses. A cryptic predator causing overall low-intensity responses favoured central attacks, showing that the magnitude of the prey's defence is driving predator attack strategies. Additionally, we report priming effects where repeated attacks in spatial proximity intensified the prey's response, leading to predator species spacing attacks farther apart, suggesting priming counters sequential hunting strategies. We highlight the complex behavioural patterns underlying predator-prey dynamics in the wild, while mechanistic aspects of collective priming prompt interesting future research directions.