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Providing evidence to improve practice

Action: Provide supplementary food for gulls, terns and skuas to increase adult survival Bird Conservation

Key messages

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A randomised, replicated and controlled study in the Antarctic found that female south polar skuas Catharacta maccormicki that were fed lost more weight whilst feeding two chicks than unfed birds. There was no difference for birds with single chicks, or male birds.


Supporting evidence from individual studies


A randomised, replicated and controlled trial on King George Island, Antarctic Peninsula, in the boreal summer of 2000-1 (Ritz 2006) found that female south polar skuas Catharacta maccormicki (also Stercorarius maccormicki) that were fed when raising two chicks lost significantly more weight than control (unfed) females (average loss of 7.9% of body weight for fed pairs vs. 4.6% for controls). There was no such effect in male skuas (average loss of 2.1% of body weight for 27 fed males vs. 5.5% for 27 controls) or if females raising single chicks were included in results (loss of 6.9% of body weight for 27 fed pairs vs. 4.5% for 27 controls). Supplementary food consisted of 25-100 g of fish provided to adults every other day, corresponding to approximately 20% of a chick’s daily energy needs. This study also includes the impact of feeding on chick growth and survival, see ‘Provide supplementary food to increase reproductive success’.


Referenced papers

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. (2019) Bird Conservation. Pages 141-290 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.