Real-time context-dependent cooperation in parental provisioning reveals fitness payoffs in barn owls.

Parental cooperation in species with extended biparental care is essential for offspring survival, yet real-time negotiation and coordination in the wild remain poorly understood. We simultaneously Global Positioning System (GPS)- and accelerometer-tracked 68 breeding pairs of barn owls (Tyto alba) during chick rearing, quantifying parents' hunting effort, prey deliveries, self-feeding, nest attendance, and partner encounters. Within pairs, parental investment was highly plastic, with low repeatability of nightly provisioning shares. Females increased provisioning when males underperformed or when foraging habitat was likely poor. Parents synchronized foraging schedules and nest visits, exhibiting turn-taking-like coordination; pairs that shared provisioning more equally foraged in parallel overnight and met frequently at the nest. We detected sequential, between-night adjustments, whereby effort on one night influenced provisioning the next. Pairs maintaining more equitable care achieved higher survival and growth in their later-hatching nestlings. Our findings demonstrate how high-resolution biologging reveals dynamic behavioral mechanisms underpinning flexible biparental care under ecological variability.