Action Synopsis: Bird Conservation About Actions

Remove ectoparasites from feathers to increase survival or reproductive success

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

Study locations

Key messages

  • A replicated and controlled study in the UK found that red grouse Lagopus lagopus scoticus treated with spot applications had lower tick and disease burdens and higher survival than controls, whilst birds with impregnated tags had lower tick burdens only.
  • A replicated ex situ study in Hawaii found that CO­2 was the most effective way to remove lice from feathers, although this treatment did not kill the lice.


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 and controlled study in 1995-6 on a grouse moor in Morayshire, Scotland (Laurenson et al. 1997), found that red grouse Lagopus lagopus scoticus treated with spot applications of deltamethrin had significantly lower tick burdens, compared to control birds, significantly lower louping ill virus (LIV) infections and higher survival rates at ten weeks old compared with controls (82% survival for seven treated broods vs. 64% for seven controls). Chicks treated with lambdacyhalothrin-impregnated (tick-removal) tags also had lower tick burdens than controls, as did chicks from broods where mother only was treated (0-0.1 immature ticks/chick for broods with treated chicks vs. 0.5-0.7 for broods with treated hens and 1.4-2.3 for controls), but they did not have lower LIV infection rates or increased survival to ten weeks old.

    Study and other actions tested
  2. A replicated ex situ study in Hawaii (Visnak & Dumbacher 1999) tested four different fumigants (chloroform, di-ethyl ether, ethyl acetate and carbon dioxide, CO2) to assess the efficiency and speed with which they immobilised and detached slender pigeon lice Columbicola columbae from the feathers of feral pigeons Columba livia. CO2 was fastest in immobilising lice (average of 61 s for three trials of ten lice), followed by chloroform (122 s), ethyl acetate (198 s) and ether (201 s). CO2 was also fastest at detaching lice from feathers (average of 181 s for 30 lice) followed by chloroform (192 s), ethyl acetate (293 s) and ether (307 s). However, CO2 only detached 22% of lice, compared to 33% for ethyl acetate, 56% for ether and 76% for chloroform. In addition, CO (unlike the other chemicals) did not kill the lice, which quickly recovered when given fresh air.

    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

All the journals searched for all synopses

Bird Conservation

This Action forms part of the Action Synopsis:

Bird Conservation
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What Works in Conservation

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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