Sparrowhawk Accipiter nisus presence and winter bird abundance

Publication Type:Journal Article
Year of Publication:2009
Authors:Chamberlain, D, Glue, D, Toms, M
Journal:Journal of Ornithology
Date Published:2009
ISBN Number:2193-7192
Keywords:Accipiter, Accipiter nisus, Accipitridae, Carduelis, Carduelis chloris, Chloris, Chloris chloris, Cyanistes, Cyanistes caeruleus, Fringilla, Fringilla coelebs, Fringillidae, Nisus, Paridae, Parus, Parus caeruleus, Parus major, Streptopelia decaocto, Sturnidae, Sturnus, Sturnus vulgaris
Abstract:The decline and subsequent re-colonisation of the Sparrowhawk Accipiter nisus in the UK has allowed an examination of its potential impacts on passerine abundance through analysis of long-term garden bird monitoring data. Weekly counts in gardens in winter have been collected annually since the early 1970s, a period when Sparrowhawks were initially rare but recolonised to a point in the 1990s when they were recorded in the majority of gardens. Change in bird count from year-to-year for 10 common prey species from up to 483 survey sites were analysed in relation to Sparrowhawk re-colonisation, the number of feeding units per site (e.g. bird tables, hanging bird feeders) and, for a subset of the data, minimum temperature. Year-to-year change increased with Sparrowhawk re-colonisation in Great Tit Parus major , Blue Tit Cyanistes caeruleus and Collared Dove Stretopelia decaocto , but decreased in Starling Sturnus vulgaris , Chaffinch Fringilla coelebs and Greenfinch Carduelis chloris . Positive associations may suggest a behavioural response to predators, or an attraction of predators to increased prey caused by confounding effects of improvement in site quality. The significant negative effects detected suggest that there is a temporal matching between increased predation pressure and decreases in bird abundance for certain species. However, there was no strong evidence that Sparrowhawk re-colonisation was linked to long-term declines in population size.
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith