Parental Provisioning in an Urban Apex Predator.

We combine high-definition webcams and citizen science to explore parental care in urban peregrine falcons Falco peregrinus (hereafter 'peregrines') from 30 locations across England between 2019 and 2023. By analysing detailed webcam footage, we quantified changes in prey type and delivery rates as nestlings developed. Common starlings Sturnus vulgaris and pigeons Columba livia , both feral and domestic (loft), dominated the prey brought to the nest, with a progressive increase in the proportion of the larger species as nestlings aged. There was an initial increase in the rate of prey delivery from hatching until nestlings reached 9-12 days old, modulated to a degree by brood size, but thereafter delivery rates dropped progressively until fledging. Somewhat unexpectedly, there was no evidence for the total mass and energy supplied over the nestling period varying with brood size. This study provides valuable insights into the breeding ecology of urban-dwelling peregrines and highlights the value of citizen science and technology in wildlife research.