Early Bird Special: Quantifying Tiger Shark Predation on Albatross Fledglings at Kure Atoll

Predator-prey interactions can be structured by predictable seasonal pulses in prey availability, yet direct evidence of temporal dynamics of predator presence, prey availability, and predation success remains scarce in marine systems. At albatross (Phoebastria immutabilis and P. nigripes) fledging colonies, tiger shark (Galeocerdo cuvier) aggregations are a recurring seasonal event, but the timing and dynamics of these interactions have yet to be measured. We directly quantified these interactions throughout an entire fledging season at Kure Atoll, Northwestern Hawaiian Islands. We examined temporal variation in surface-visible predator sightings and prey abundance, environmental drivers, predation success, and seasonal patterns in predation risk. Tiger shark sightings peaked 28 days prior to peak fledgling abundance, suggesting a temporal mismatch between predator and prey, whereby sharks preferentially target early stages of prey availability when fledglings are most vulnerable, rather than periods of highest prey abundance. Environmental variables had weak and uncertain effects on both predator sightings and prey abundance, with temporal structure found as the dominant driver of observed patterns. Low strike efficiency by tiger sharks on fledglings was observed with high overall success once interactions occurred, indicating that repeated attack attempts contribute substantially to successful predation outcomes. Predation risk peaked early in the fledging season, primarily driven by temporal overlap between predator and vulnerable prey rather than changes in predator behavior or overall prey abundance. More broadly, our findings suggest that predator responses to predictable prey pulses may be shaped by variations in prey vulnerability, highlighting a key mechanism linking predator behavior to ecological patterns of predation.