Action Synopsis: Bird Conservation About Actions

Provide refuges for fish within ponds

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

Study locations

Key messages

A controlled cross-over trial in the UK found that great cormorant Phalacrocorax carbo foraging success was lower in a pond with artificial refuges, compared to a control pond.


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. In Berkshire, England, a controlled cross-over trial (in the winters of 2003 and 2004) found that great cormorant Phalacrocorax carbo foraging success was lower in a pond with artificial refuges (Russell et al. 2008), compared to a control pond (on average, 67% less fish weight consumed/cormorant visit); fish loss was significantly lower (79% less fish weight lost); and there were 77% fewer cormorant visits. Two adjacent ponds (45.0 x 27.2 m; 1.35 m depth) were used, with provided in one pond each year. Refuges were 12 mesh covered cages (2 x 2 x 1.2 m high) in two blocks of six, with shade cloth and containing 4-6 tree saplings to provide cover. At commencement of each trial, ponds were similarly stocked with freshwater fish. Fish weight was recorded at the beginning and end of each trial.

    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?

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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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