Research Project

Corvid Breeding Biology

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Corvids are well established as predators of nests of songbirds at the egg and nestling stage, yet relatively little is known about the natural history and behaviour of these corvids. This project aimed to investigate the susceptibility of magpies to control methods and provide solutions to lessen the impact of predation on populations.

The Project

SongBird Survival jointly funded a PhD studentship with the Game and Wildlife Conservation trust and the University of Exeter in 2014. This project was commissioned to examine corvid breeding behaviour, as large-scale analyses of relationships between population trends of corvids and songbirds do not show the expected negative relationship, and the experimental removal of corvids has mixed effect on songbird productivity. One explanation for this confused picture is that some individuals may be disproportionately prolific nest predators. Large numbers of corvids may be removed, but if these ‘super-predators’ are not amongst them, then an increase in productivity may not be seen. If we know more about corvid behaviour, we may be able to minimise any damage that they cause to particularly at-risk song and other small bird populations.

This research looked at:

  • The predation of 460 artificial nests in 24 hedgerow locations in UK farmland to ascertain key predators of songbird nests with cameras and with wax-filled eggs.
  • Whether there is a temporal element to the predation of nests by presenting nests from April until July.
  • Monitoring magpie breeding dates and territories to assess if this would influence predation of nests. Individuals were identified with coloured rings and their breeding status determined.
  • Habitat variation within breeding sites and whether hedgerow management may influence levels of predation.
  • Reviewing the available literature to understand what factors predict how susceptible songbirds are to predation.

By increasing understanding of predation of songbird nests, this work will help inform more effective and better-targeted countryside management to benefit Britain’s threatened songbirds. There is so much we still don’t know about songbirds, the world they live in and how to protect them, these same thoughts were echoed by David Attenborough:

“Birds are the most popular group in the animal kingdom. We feed them and tame them and think we know them. And yet they inhabit a world which is really rather mysterious.”

The Results

  • 133 of 460 nests were predated during the experiment (approximately 29%) Medium sized birds were found to be the most frequent predator (in 70.3% of predation events that were identified).
  • Small mammals were identified as predators in 23.5% of cases (mostly brown rats) and several events of other small and songbirds predating nests were also seen.
  • Corvids were the only medium-sized birds identified on camera to predate nests. 87.5% of these corvids were identified as magpies.
  • Nest location significantly affected predation rates. Higher predation at these locations appeared to be driven by increased predation by magpies in that area.
  • When looking at all predator types (including mammals and small birds), predation rates decreased over time. However, when considering only predation by medium-sized birds, nests close to magpie nests were more likely to be predated late in the season. This coincides with provisioning of magpie chicks and fledglings.
  • Individual magpies appeared to differ in their propensity to predate nests, so it is likely that only certain individuals are responsible.
  • Of the 80 papers reviewed, the magpie and/or jay was identified as nest predators in 93% of studies where individual corvids could be identified.
  • Across all studies, around 24% of nest predation was due to corvids, with a mean of ~10% of nests/eggs lost to this predation.
  • Open nesting species received higher levels of predation by corvid predator’s vs hole nesting species.
  • Songbirds that had more of their breeding seasons overlap with magpie and jay also suffered higher levels of corvid predation.

The Solutions

This project highlighted the difficulties in creating a management strategy that universally benefits songbirds and limits predation. Management strategies considered to protect songbirds should consider all predator species in the community due to their interactions and external factors. That said, the corvid breeding biology project produced several solutions to the issue of corvid predation.

  • Providing suitable habitat within properly managed hedgerows and nest boxes (with predator proof entrances) would be of great benefit to songbird species to protect from predation events
  • Providing hedgerows that have a mix of trees and bushes that grow year-round provide constant shelter from predatory species
  • As each songbird species is affected differently by corvids, providing plentiful food during peak magpie/jay breeding season (March-July) may provide them some relief.
  • In some cases, predator removal may be needed to assist at-risk songbird species.

For more tips and advice on how best to encourage birds to your garden, click here.

Meet our scientists

What is a Songbird?

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Dr Lucy Capstick

Research Ecologist- GWCT

Lucy is a research ecologist, now focusing on agricultural ecology with GWCT. Her current research is focused on pollinators and crop pollination. In particular, she is examining how flower-rich habitats in agricultural landscapes affect the number of pollinators and the pollination of field bean crops as part of the BEESPOKE project within the Game & Wildlife Conservation Trust.



Capstick, L.A., Madden, J.R. (2021) Factors predicting susceptibility of songbirds to nest predation by corvids. European Journal of Wildlife Research. 67:  

Capstick, L.A., Sage, R.B., Madden, J.R. (2019) Predation of artificial nests in UK farmland by magpies (Pica pica): interacting environmental, temporal, and social factors influence a nest’s risk. European Journal of Wildlife Research. 65:  

Related Studies

Dunn, J.C., Gruar, D., Stoate, C., Szczur, J., Peach, W.J. (2016) Can hedgerow management mitigate the impacts of predation on songbird nest survival? Journal of Environmental Management. 184(3): 535-544.  

Madden C, Arroyo B, Amar A (2015) A review of the impacts of corvids on bird productivity and abundance. Ibis. 157:1–16

Smith R.K., Pullin A.S., Stewart G.B. & Sutherland W.J. (2010) Effectiveness of predator removal for enhancing bird populations. Conservation Biology. 24: 820-829.

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J., Sutherland, W.J. (2020) Bird Conservation. pp 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

See our publication library for more of our research.