The effectiveness of land-based schemes (incl. agri-environment) at conserving farmland bird densities within the UK. CEE Review 05-005

Published source details Roberts P.D. & Pullin A.S. (2007) The effectiveness of land-based schemes (incl. agri-environment) at conserving farmland bird densities within the UK. CEE Review 05-005. CEE (Collaboration for Environmental Evidence) Systematic Reviews, SR11.
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This study is summarised as evidence for the following.

	Action	Category
	Leave overwinter stubbles Action Link
	Leave overwinter stubbles Action Link
	Pay farmers to cover the costs of bird conservation measures Action Link
	Provide or retain set-aside areas in farmland Action Link
	Plant wild bird seed or cover mixture Action Link
	Pay farmers to cover the cost of conservation measures (as in agri-environment schemes) Action Link
	Plant wild bird seed or cover mixture Action Link
	Provide or retain set-aside areas in farmland Action Link

Leave overwinter stubbles

A 2007 systematic review identified five papers investigating the effect of overwinter stubble provision on farmland bird densities in the UK (Roberts & Pullins 2007). There were significantly higher densities of farmland birds in winter on fields with stubbles than on conventionally managed fields. In particular, there were greater densities of seed-eating songbirds and crows on fields with stubbles than on control fields. The meta-analysis included experiments conducted between 1992 and 2002 from three controlled trials, before-and-after study, and one site comparison study.
Leave overwinter stubbles

A 2007 systematic review identified five papers investigating the effect of overwinter stubble provision on farmland bird densities in the UK (Roberts & Pullin 2007). There were significantly higher densities of farmland birds in winter on fields with stubbles than on conventionally managed fields. In particular, there were greater densities of seed-eating songbirds and crows (Corvidae) on fields with stubbles than on control fields. The meta-analysis included experiments conducted between 1992 and 2002 from three controlled trials, one time series, and one site comparison study.
Pay farmers to cover the costs of bird conservation measures

A 2007 systematic review of 29 studies incorporating data for 15 farmland bird species in the UK (Roberts & Pullin 2007) found that there were significantly higher winter densities of farmland birds on fields under agri-environment schemes than on conventionally managed fields. Considering each scheme individually, there was greater winter densities of birds on fields within the Arable Stewardship Pilot Scheme, Countryside Stewardship Scheme, fields with set-aside, overwinter stubble, and wild bird cover than on conventionally farmed fields. Overall, eight species (53%) had significantly higher winter densities on agri-environment fields compared to conventional cropping (corn bunting, greenfinch, grey partridge, northern lapwing, linnet, rook, Eurasian skylark and song thrush Turdus philomelos) and no species were found to have higher densities on conventional agricultural fields compared to those fields entered under agri-environment scheme agreements. Although set-aside fields in summer had significantly higher densities of farmland birds, there was no difference between the number of birds on conventionally farmed fields and Arable Stewardship Pilot Schemes fields in summer. Six (35%; grey partridge, northern lapwing, woodpigeon, Eurasian skylark, rook and cirl bunting) of the 17 species for which summer data were available were found at significantly higher densities on agri-environment scheme fields compared with fields under conventional systems. The migratory yellow wagtail Motacilla flava was found at lower densities on scheme fields than on conventionally managed fields. In total 29 papers describing experiments conducted between 1985 and 2005 on a total of 12,653 fields (5,381 fields under agri-environment schemes and 7,272 fields farmed conventionally) were used for the meta-analysis. The meta-analysis included seven site comparison studies, five randomised control trials and 17 controlled trials.
Provide or retain set-aside areas in farmland

A 2007 systematic review identified 11 papers investigating the effect of set-aside provision on farmland bird densities in the UK (Roberts & Pullin 2007). In both winter and summer surveys there were significantly higher densities of farmland birds on fields removed from production and under set-aside designation than on conventionally farmed fields. The meta-analysis included experiments conducted between 1988 and 2002 from eight controlled trials and three site comparison studies.
Plant wild bird seed or cover mixture

A 2007 systematic review identified five papers investigating the effect of winter bird cover on farmland bird densities in the UK (Roberts & Pullins 2007). There were significantly higher densities of farmland birds in winter on fields with winter bird cover than on adjacent conventionally managed fields. The meta-analysis included experiments conducted between 1998 and 2001 from two controlled trials and one randomised control trial.
Pay farmers to cover the cost of conservation measures (as in agri-environment schemes)

A 2007 systematic review of 29 studies incorporating data for 15 farmland bird species in the UK (Roberts & Pullin 2007) found that there were significantly higher winter densities of farmland birds on fields under agri-environment schemes than on conventionally managed fields. Considering each scheme individually, there were greater winter densities of birds on fields within the Arable Stewardship Pilot Scheme, Countryside Stewardship Scheme, organically farmed fields, fields with set-aside, overwinter stubble, and wild bird cover than on conventionally farmed fields. Overall, eight species (53%) had significantly higher winter densities on agri-environment fields compared to conventional cropping (corn bunting Miliaria calandra, greenfinch Carduelis chloris, grey partridge Perdix perdix, northern lapwing Vanellus vanellus, linnet C. cannabina, rook Corvus frugilegus, Eurasian skylark Alauda arvensis and song thrush Turdus philomelos) and no species were found to have higher densities on conventional agricultural fields compared to those fields entered under agri-environment scheme agreements. Although both organic fields and set-aside fields in summer had significantly higher densities of farmland birds, there was no difference between the number of birds on conventionally farmed fields and Arable Stewardship Pilot Scheme fields in summer. Six species (35%; grey partridge, lapwing, woodpigeon Columba palumbus, skylark, rook and cirl bunting Emberiza cirlus) of the 17 for which summer data were available were found at significantly higher densities on agri-environment scheme fields compared with fields under conventional systems. The migratory yellow wagtail Motacilla flava was found at lower densities on scheme fields than on conventionally managed fields. In total 29 papers describing experiments conducted between 1985 and 2005 on a total of 12,653 fields (5,381 fields under agri-environment schemes and 7,272 fields farmed conventionally) were used for the meta-analysis. The meta-analysis included seven site comparison studies, five randomized controlled trials and 17 controlled trials.
Plant wild bird seed or cover mixture

A 2007 systematic review identified five papers investigating the effect of winter bird cover on farmland bird densities in the UK (Roberts & Pullin 2007). There were significantly higher densities of farmland birds in winter on fields with winter bird cover than on adjacent conventionally managed fields. The meta-analysis included experiments conducted between 1998 and 2001 from two controlled trials and one randomized control trial.
Provide or retain set-aside areas in farmland

A 2007 systematic review (Roberts & Pullin 2007) identified 11 papers investigating the effect of set-aside provision on farmland bird densities in the UK. In both winter and summer surveys there were significantly higher densities of farmland birds on fields removed from production and under set-aside designation than on conventionally farmed fields. The meta-analysis included experiments conducted between 1988 and 2002 from eight controlled trials and three site comparison studies.