Action Synopsis: Bird Conservation About Actions

Reduce nest ectoparasites by providing beneficial nesting material

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

A randomised, replicated and controlled experiment in Canada found lower numbers of some, but not all, parasites in nests provided with beneficial nesting material, but that there was no effect on fledging rates or chick condition.


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 randomised, replicated and controlled experiment in 2000 at four sites in New Brunswick and Nova Scotia, Canada (Shutler & Campbell 2007) found that the number of purple martin fleas Ceratophyllus idius was significantly lower in tree swallow Tachycineta bicolor nests with fresh yarrow Achillea millefolium foliage added every two days whilst clutches were being laid, compared to control nests with no added foliage (419 fleas/nest for 23 experiomental nests vs. 773 fleas/nest for 44 controls). There were no corresponding differences in the number of blowfly Protocalliphora spp. pupae  (3.3 and 2.5 pupae/nest for experimental and control nests respectively), nestling mass (23.5 g in experimental nests vs. 23.8 g in controls), nestling leukocyte profiles, or proportion of young fledging (5.3 fledglings/nest for experimental nests vs. 5.1 fledglings/nest for controls). The authors speculate that adult tree swallows may increase provisioning rate to compensate for flea parasitism.

    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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