Action Synopsis: Bird Conservation About Actions

Use collar-mounted devices to reduce predation

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms
    not assessed

Study locations

Key messages

  • Two replicated randomised and controlled studies in the UK and Australia found that significantly fewer birds were returned by cats wearing collars with various anti-hunting devices, compared to controls.
  • A replicated, randomised and controlled study from the UK found no significant differences between different devices.
  • Both UK studies found that collars were easily lost.


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

  1. A replicated, randomised and controlled study across the UK between April and August 2002 (Nelson et al. 2005) found that for a total of 89 cats, fewer birds were returned by those fitted with a collar and bell (41% reduction and 74 birds) or a collar with a ‘CatAlert™’ sonic device (51% reduction and 59 birds) than by cats with a plain collar (117 birds). The difference between bell and ultrasound was not significant. A second replicated and randomised study between May and September 2003 found that, for a total of 67 cats, the number of birds returned by cats was not significantly affected by whether cats were wearing collars with one bell, two bells or ‘CatAlert™’ sonic devices. In both trials, the authors note that collars were easily lost, with a total of 55 sonic device, 39 one-bell, 16 two-bell and 21 plain collars lost (and replaced) over the study. The authors also note that that this study does not support the assertion that cats can learn to adapt hunting to render bells less effective.

    Study and other actions tested
  2. A replicated, randomised and controlled study in Perth, Australia in November-December 2005 (Calver et al. 2007) found that wearing a ‘CatBib™’ “pounce protector” (a neoprene flap that hangs from a collar in front of a cat’s front legs, acting either as a visual warning or as a barrier to pouncing) for three weeks, reduced the number of cats catching birds by 81% compared to when the same cats were not wearing the ‘CatBib™’ (5 vs. 26; n = 56 cats). The average number of birds captured per cat was also significantly lower (0.29 vs. 0.88). Adding a bell to the ‘CatBib™’ did not further reduce hunting.

    Study and other actions tested
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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Bird Conservation

This Action forms part of the Action Synopsis:

Bird Conservation
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What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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