Action Synopsis: Bird Conservation About Actions

Provide supplementary food for vultures to increase adult survival

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

Study locations

Key messages

  • A before-and-after study from Spain found a large increase in griffon vulture Gyps fulvus population in the study area following multiple interventions including supplementary feeding.
  • Two studies from the USA and Israel found that Californian condors Gymnogyps californianus and Egyptian vultures Neophron percnopterus fed on many of the carcasses provided for them. The Egyptian vultures were sometimes dominated by larger species at a feeding station supplied twice a month, but not at one supplied every day.


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 study in California, USA, between February 1971 and May 1973 (Wilbur et al. 1974) found that Californian condors Gymnogyps californianus fed on at least 47 of 83 carcasses provided over the study period. Another 27 carcasses may well have been fed on and the remaining nine were taken by black bears Ursus americanus before condors could feed. Carcasses were mainly mule deer Odocoileus hemionus. This study is also discussed in ‘Provide supplementary food to increase reproductive success’.

    Study and other actions tested
  2. A before-and-after between 1969 and 1989 in the western Pyrenees, Spain (Donazar & Fernandez 1990), found that the population of griffon vultures Gyps fulvus increased from 282 pairs (in 23 colonies) in 1969-75 to 1,097 pairs (46 colonies) in 1989 following the initiation of multiple conservation interventions including the installation of feeding stations between 1969 and 1979. However, the authors note that only two of six feeding stations were used by vultures and food was never apparently a limiting factor for the population in the study area. This study is also discussed in ‘Habitat protection’, ‘Restrict certain pesticides or other agricultural chemicals’ and ‘Use legislative regulation to protect wild populations’.

    Study and other actions tested
  3. A study in the Negev Desert, Israel, in April-August of 1989 and 1990 (Meretsky & Mannan 1999) found that adult Egyptian vultures Neophron percnopterus were able to dominate a feeding station supplied daily with 5-10 kg of chicken, but not a station supplied approximately twice a month with large amounts (20-350 kg) of meat. Peak numbers of vultures were higher at the irregularly-stocked station (30-40 vultures present at once vs. 20-30) but they were sometimes excluded by mammals (e.g. striped hyaena Hyaena hyaena) or Eurasian griffon vultures Gypus fulvus, which did not occur at the regularly-stocked station.

    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 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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