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The BTO House Sparrow Survey The presentation given by Mike Toms at the Defra House Sparrow Conference centred on the BTO House Sparrow Survey carried out through the BTO/CJ Garden BirdWatch Project. Some of the slides from the presentation may be downloaded from this page and these appear alongside a set of notes outlining the main points of the talk. Click on the slide title to open the slide image. Slide 5 (GBFS): House Sparrow populations living within human habitats have been in decline since the mid-1980s, as shown by results from the BTO Garden Bird Feeding Survey (GBFS). While the GBFS provides a national picture it does not tell us about seasonal variation in the use made of gardens, nor does it tell us about regional variation in the pattern of decline. Slide 6 (GBW): The BTO/CJ Garden BirdWatch project (GBW) is the BTO's main means of monitoring how birds use gardens. Because the project involves some 17,000 participants it can provide very valuable regional information that can help us unravel regional variation in the decline of House Sparrows. Slide 9. (Questionnaire 1): As part of the Garden BirdWatch project the BTO has been running a two-pronged study of House Sparrow populations in urban and suburban areas. The first part of this involved a questionnaire study in which detailed questions were asked about the habitats, food availability, nest sites, predators and competitors of House Sparrows. The preliminary results of this work can be viewed by clicking here. Slide 12. (Questionnaire results 1): Useable responses were received from 11,269 gardens and showed that House Sparrows were more likely to occur at sites where there were still gaps in the roof tiles or under the eaves. Worringly, more than 25% of respondents had blocked these holes, with 7% having done so within the last 12 months. 90% of respondents had loft insulation, which again may reduce the availability of nest sites. Slide 13. (Questionnaire results 2): The results also showed that gardens in which food was provided year-round were more likely to have House Sparrows than once that only fed occasionally or not at all. Surrounding habitats were found to be important and it appeared that parks, schools and wasteground were important for urban populations. Interestingly, more dead sparrows were found dead in gardens near busy roads than in gardens away from busy roads. House Sparrows were more likely to be found at sites where potential predators and competitors were present. This may seem counter-intuitive but it probably reflects similar habitat preferences for all the species concerned. Slide 15. (GIS): The second component of the study is still ongoing and is looking at House Sparrow populations in a series of randomly selected squares spread across an urban-suburban-rural gradient. Survey squares were selected by mapping the degree of urbanisation onto 10-km squares spread across Britain (see slide, which picks out urban areas). Slide 20. (Habitat mapping). The habitats within these survey squares were carefully mapped by the 1,500 participants so we could examine which habitats sparrows were using at different times of year. Slide 23. (Sparrow locations). During two breeding seasons and one winter season, the locations of House Sparrows (flocks and individuals) plus cats, Sparrowhawks and Magpies were mapped. During 2004 we shall be examining the results of this work. Slide 25. (Pulling it together). Information from the two components of the survey, plus additional information from Garden BirdWatch gardens and previous BTO work.
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