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Providing evidence to improve practice

Action: Provide supplementary food for raptors to increase adult survival Bird Conservation

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.

 

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’.

 

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’.

 

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. (2018) Bird Conservation. Pages 95-244 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2018. Open Book Publishers, Cambridge, UK.