Action

Action Synopsis: Bird Conservation About Actions

Provide supplementary food for raptors to increase adult survival

How is the evidence assessed?
  • Effectiveness
    30%
  • Certainty
    23%
  • Harms
    0%

Source countries

Key messages

Two randomised, replicated and controlled studies in the USA found that nesting northern goshawks Accipiter gentilis were significantly heavier in territories supplied with supplementary food, compared with those from unfed territories.

 

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 trial in mixed conifer forests and scrub in New Mexico, USA, in 1992-3 (Ward & Kennedy 1996), found that northern goshawk Accipiter gentilis adults from territories provided with supplementary food during nesting were heavier than adults from control (unfed) territories, but sample sizes were too small for statistical tests (females: average of 1,007 g for six birds from fed territories vs. 975 g for five controls; males: average of 689 g for five fed territories vs. 660 g for two controls). Supplementary food consisted of dead Japanese quail Cortunix japonica provided every other day starting the day after hatching and continuing until most control birds left the area. This study also examined differences in chick growth and survival, discussed in ‘Provide supplementary food to increase reproductive success’.

    Study and other actions tested
  2. A randomised, replicated and controlled trial in mixed conifer forests in Utah, USA, in 1996-7 (Dewey & Kennedy 2001), found that northern goshawk Accipiter gentilis females from territories provided with supplementary food (Japanese quail Coturnix japonica provided from close to hatching to chick independence) were significantly heavier than those from control (unfed) territories (1,104 g for eight fed females vs. 993 g for nine controls). This study also examined differences in chick growth and survival, discussed in ‘Provide supplementary food to increase reproductive success’.

    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

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, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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