Nest predation is a major cause of breeding failure in many bird species, and understanding the species responsible for this is important in designing effective conservation interventions. This study brought together data collected by camera traps in the UK and Ireland to help identify key nest predators and highlight any knowledge gaps.

Using data from 2,088 nests which included 609 predation events, the study assessed 24 prey species focusing primarily on waders and passerines. Predators varied by the prey groups, with wader clutches predominantly taken by mammals, including Foxes, Badgers, Hedgehogs (on the Hebrides) and Sheep. Passerine predation was more evenly spread between birds and mammals. Of the avian predators, Jays were major consumers of passerine eggs, and raptors were frequently captured predating on chicks. Grey Squirrels and Magpies were rarely recorded predating passerine nests.

All the available nest camera data analysed in this study were mostly from grassland and woodland habitats, with few records from farmland and urban areas. This means that both some prey (e.g. scrub/hedgerow- and cavity-nesting species, and gamebirds) and some predators (e.g. domestic Cats and Dogs) were not well represented. More nest camera studies are therefore required to provide robust and representative evidence linking predators and prey in order to inform policy and legislation about predator control.

Nest predation is the primary cause of nest failure across many bird species. Interventions to support declining or threatened species frequently involve measures to reduce nest predation, through lethal control or non-lethal methods; their efficacy relies on a robust understanding of predator identity. The development of unobtrusive, infrared digital video surveillance now allows the identity of nest predators to be confirmed directly. Here, we collate and analyse nest camera studies from England, Wales, Scotland and the Isle of Man, that are dominated by anthropogenic landscapes and lacking most apex predators, but with a high abundance of mesopredators. We quantify the contribution of predator class and functional groups across groups of prey species, nesting habitats or nest strata. For quantitative analysis we collated 46 nest predation studies, comprising 2088 nests and 609 predation events across 24 avian prey species. Nest predation studies are not yet representative, mostly comprising Waders (Chardriiformes) and a few passerines, in grassland and woodland habitats respectively, with farmland and urban habitats poorly sampled. Wader clutches were predominantly predated by mammals (primarily European Badger Meles meles; and Red Fox Vulpes vulpes; and particularly on islands European Hedgehog Erinaceus europaeus; together 53% of events), but with non-trivial contributions of ungulates (6%), predominantly Sheep Ovis aries. Passerine clutches were predated by corvids (31% of events) and mammals (primarily Badger and Fox, 25% combined). Compared to depredation of passerine clutches, passerine broods were taken by a wider range of predators particularly avian predators, predominantly Eurasian Jay Garrulus glandarius (23% of events, though noting 73% of songbird predation events were in woodland) and raptors (21%), but also reptiles. Despite the attention given to impacts of Grey Squirrel Sciurus carolinensis, its contribution to observed nest predation was negligible. Further work is required to expand understanding of nest predator identity, to improve understanding of changing predator influences across populations, so that, where appropriate for conservation, management strategies can be better informed.