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Providing evidence to improve practice

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

Key messages

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  • One replicated, controlled study from the USA found that 12 female downy woodpeckers Picoides pubescens supplied with supplementary food had higher nutritional statuses than unfed birds.
  • However, two analyses of a replicated, controlled study of 378 downy woodpeckers from the USA found that they did not have higher survival rates or nutritional statuses than unfed birds.

 

Supporting evidence from individual studies

1 

A replicated, controlled study in deciduous forests in Ohio, USA, in the winter of 1988-9 (Grubb & Cimprich 1990) found that 12 female downy woodpeckers Picoides pubescens grew longer feathers and grew them faster (a proxy for nutritional condition) when supplied with sunflower seeds and suet in excess, compared to six unfed control females. There were no such differences in eight fed and nine control male woodpeckers. The impact on three songbird species is discussed in ‘Provide supplementary food to increase adult survival – Songbirds’.

 

2 

A replicated, controlled study in 54 woodlots and riparian corridors in an agricultural landscape in Ohio, USA, in the winters of 1995-9 (Doherty & Grubb 2002) found that 378 downy woodpeckers Picoides pubescens did not have higher survival rates in either woodlots or riparian strips provided with supplementary food, compared with unfed, control sites. The impact on three songbird species is discussed in ‘Provide supplementary food to increase adult survival – Songbirds’. Supplementary food consisted of sunflower seeds and suet provided in excess throughout winter.

 

3 

Another analysis (Doherty & Grubb 2003) of the same data as Doherty & Grubb 2002 found that downy woodpeckers Picoides pubescens did not have higher nutritional statuses (judged by the size of feather growth bars) than woodpeckers in unfed control woodlots. The impact on three songbird species is discussed in ‘Provide supplementary food to increase adult survival – Songbirds’.

 

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.