Individual study: Effects of supplementary winter feeding on great tits Parus major and blue tits P. caeruleus in deciduous woodland near Lund, Skåne,, Sweden
Källander H. (1981) The effects of provision of food in winter on a population of the great tit Parus major and the blue tit P. caeruleus. Ornis Scandinavica, 12, 244-248
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 songbirds to increase adult survival
A replicated, controlled study in the winters of 1969-71 in three deciduous woods in southern Sweden (Källander 1981) found that great tit Parus major populations increased at two fed sites but declined at an unfed control site in a harsh winter, but increased at all sites in a milder winter. Adult survival over this period was highest in the site fed in both years (37-59% survival of 31 birds), intermediate in the control site (35-47% survival of 22) and lowest at the site fed only in 1969-70 (13-19% survival of seven). More yearlings remained in the two fed sites, compared with the control (14-22% of 85 birds remaining vs. 7-11% of 48). Blue tit P. caeruleus populations appeared unaffected by feeding at the same sites. Supplementary food consisted of hoppers filled with sunflower seeds provided from December (1969) or October (1970) until March.