Remove or control predators to enhance bird populations and communities

Overall effectiveness category Beneficial
Number of studies: 2
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How is the evidence assessed?

Effectiveness

66%
Certainty

71%
Harms

not assessed

Calculating overall effectiveness category

Key messages

A meta-analysis and a systematic review both found that reproductive success increased with predator removal, but their exact findings differed.
The meta-analysis found that post-breeding population size increased, whilst the systematic review found that this was true on mainlands, but not islands and that breeding populations also increased.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A meta-analysis of 20 published studies (Côté & Sutherland 1997) showed that predator removal had a large, positive effect on hatching success – with removal areas showing higher hatching success on average than 75% of control areas – and led to a significant increase in post-breeding population size (i.e. autumn density), although no significant impact was detected on breeding population size.
Study and other actions tested
Referenced paper
Côté I.M. & Sutherland W.J. (1997) The effectiveness of removing predators to protect bird populations. Conservation Biology, 11, 395-405.
A 2010 systematic review (Smith et al. 2010) found that removing predators tended to lead to increased reproductive success (hatching and fledging success) and breeding populations in birds. On mainlands, but not islands, predator removal also tended to increase post-breeding population size. Whether predators were native or not, the population trend of the bird population and whether the species was migratory or a game species did not affect responses to predator removal.
Study and other actions tested
Referenced paper
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.

Please cite as:

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. Pages 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.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Bird Conservation

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Control mammalian predators on islands for seabirds Action Link	Beneficial	18	Synopsis Link
Control predators not on islands for songbirds Action Link	Awaiting assessment	10	Synopsis Link
Control mammalian predators on islands for pigeons Action Link	Awaiting assessment	2	Synopsis Link