Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: Translocation of black-billed magpies Pica pica increases the number of juvenile blue tits Parus caeruleus and the number of adult long-tailed tits Aegithalos caudatus, but appears to reduce the number of adult blackcaps Sylvia atricapilla and has no effect on seven other species of songbird

Published source details

Chiron F.O. & Julliard R. (2007) Responses of songbirds to magpie reduction in an urban habitat. The Journal of Wildlife Management, 71, 2624-2631


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

Reduce predation by translocating predators Bird Conservation

A paired sites before-and-after trial at two urban locations in the Paris area, France, between 2003 and 2005 (Chiron & Julliard 2007) found that the number of juvenile blue tits Parus caeruleus increased by 40% and the number of adult long-tailed tits Aegithalos caudatus increased 50 fold following the removal of 91 black-billed magpies Pica pica from experimental sites (a 58% reduction in density), with no corresponding increase in control sites where magpies were not removed. However, removal appeared to cause a 70% reduction in the number of adult blackcaps Sylvia atricapilla. There was no change in the number of juveniles or adults in seven other species.