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Providing evidence to improve practice

Individual study: The effect of supplementary winter seed food on breeding populations of farmland birds in the UK

Published source details

Siriwardena G.M., Stevens D.K., Anderson G.Q.A., Vickery J.A., Calbrade N.A. & Dodd S. (2007) The effect of supplementary winter seed food on breeding populations of farmland birds: evidence from two large-scale experiments. Journal of Applied Ecology, 44, 920-932


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Provide supplementary food for birds or mammals Farmland Conservation

A replicated study using the same data as (Siriwardena & Stevens 2004) and combining it with data from control areas between 2000 and 2003 (Siriwardena et al. 2007) did not find robust evidence for supplementary winter feeding increasing breeding abundances of farmland songbirds. There were no effects of the Bird Aid programme on target species, although sites used more frequently had increased populations of yellowhammer Emberiza citrinella and corn bunting Miliaria calandra, but decreased populations of tree sparrow Passer montanus. Four of five insect-eating/generalist species declined faster in Winter Food for Birds programme sites than in controls. There was no such effect for six seed-eating species. Declines in dunnock Prunella modularis, robin Erithacus rubecula and yellowhammer Emberiza citrinella were lower in Winter Food for Birds sites provided with more food and centrally-placed Winter Food for Birds sites, compared to those provided with less food or those around the periphery of Winter Food for Birds clusters. Results from the same experimental set-up are also presented in (Siriwardena & Stevens 2004, Defra 2005, Siriwardena et al. 2006, Defra 2007, Siriwardena et al. 2008).

 

Provide supplementary food for songbirds to increase adult survival Bird Conservation

A series of randomised, replicated trials at two sites in England in the winters of 2000-1 and 2001-2 (Siriwardena et al. 2007) found that five songbird species took supplementary food when provided and preferentially took wheat over oats and oats over barley. Tree sparrows Passer montanus and reed buntings Emberiza schoeniclus also fed on maize, preferring it to all cereals except wheat, whilst house sparrows P. domesticus preferred maize to all cereals. Corn buntings E. calandra and yellowhammers E. citrinella preferred all cereals to maize. Tree sparrows selected both cereals and oily seeds (sunflower seeds, oilseed rape etc) but avoided rye grass seed. All species preferred cereals to sunflower seeds and none showed any distinction between wheat and a ‘weed seed mix’. At one site, food was provided in tubular feeders, in the other it was heaped on the ground. Survival rates of birds were not monitored.

 

Provide supplementary food for songbirds to increase adult survival Bird Conservation

A replicated study using some of the same data as Siriwardena & Stevens 2004 and combining them with data from control areas between 2000 and 2003 did not find robust evidence for supplementary winter feeding increasing breeding abundances of farmland songbirds (Siriwardena et al. 2007). There were no effects of the Bird Aid programme on target species, although sites used more frequently had increased populations of yellowhammers Emberiza citrinella and corn buntings Miliaria calandra, but decreased populations of tree sparrows Passer montanus. Four of five insect-eating/generalist species declined faster in Winter Food for Birds (WFFB) experimental areas than in controls. There was no such effect for six seed-eating species. Declines in dunnocks Prunella modularis, robins Erithacus rubecula and yellowhammers Emberiza citrinella were lower in WFFB sites provided with more food and centrally-placed WFFB sites, compared to those provided with less food or those around the periphery of WFFB clusters.