Farmland birds and late winter food: does seed supply fail to meet demand?

Published source details Siriwardena G.M., Calbrade N.A. & Vickery J.A. (2008) Farmland birds and late winter food: does seed supply fail to meet demand?. Ibis, 150, 585-595.
Share Tweet Email

Actions

This study is summarised as evidence for the following.

	Action	Category
	Provide supplementary food for birds or mammals Action Link
	Provide supplementary food for songbirds to increase adult survival Action Link

Provide supplementary food for birds or mammals

A further study, using the same data as (Siriwardena & Stevens 2004) investigated how use of supplementary food by farmland songbirds varied over winter months (Siriwardena et al. 2008). Supplementary food-use peaked in or before January for five generalists and ‘human-associated’ seed-eating species (blackbird Turdus merula, goldfinch Carduelis carduelis, greenfinch C. chloris, house sparrow Passer domesticus and robin Erithacus rubecula), whilst yellowhammer Emberiza citrinella, reed bunting E. schoeniclus, chaffinch Fringilla coelebs and dunnock Prunella modularis all used supplementary food most in February or later. Use by great tits Parus major and blue tits P. caeruleus declined overwinter. The authors suggest the first group use food when temperatures are lowest and daylight hours shortest, whilst the second group (which are heavily dependent on farmland seed) use food when naturally-occurring food sources are at their lowest. They caution that these results are likely to be dependent on the mix of farming types across the landscape, with eastern England being dominated by arable fields. 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. 2007).
Provide supplementary food for songbirds to increase adult survival

Another study, using the same data as Siriwardena et al. 2006 and additional data from a second landscape-scale experiment, investigated how use of supplementary food by farmland songbirds varied over the winter months (Siriwardena et al. 2008). Supplementary food-use peaked in or before January for five generalists and ‘human-associated granivores (blackbirds Turdus merula, goldfinches Carduelis carduelis, greenfinches C. chloris, house sparrows Passer domesticus and robins Erithacus rubecula), whilst yellowhammers Emberiza citrinella, reed buntings E. schoeniclus, chaffinches Fringilla coelebs and dunnocks Prunella modularis all used supplementary food most in February or later. Use by great tits Parus major and blue tits P. caeruleus declined overwinter. The authors suggest food use reflects demand and the first group use food most when temperatures are lowest and daylight hours shortest, whilst the second group (which are heavily dependent on farmland seed) use food most when ambient food sources are at their most scarce and that the third group’s pattern of food use reflects the available pool of individuals as mortality occurs through the winter.. They caution that these results are likely to be dependent on the mix of farming types across the landscape, with eastern England being dominated by arable fields.