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Providing evidence to improve practice

Individual study: Numbers and breeding success of birds did not tend to differ between areas with high and low chemical inputs

Published source details

Fletcher M.R., Jones S.A., Greig-Smith P.W., Hardy A.R. & Hart A.D.M. (1992) Population density and breeding success of birds. Pages 161-174 in: G. Greig-Smith, G. Frampton & T. Hardy (eds.) Pesticides, cereal farming and the environment: the Boxworth project. HMSO MAFF, London.


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

Reduce fertilizer, pesticide or herbicide use generally Farmland Conservation

A site comparison study of arable farmland over seven years as part of the Boxworth Project in Cambridgeshire, UK (Fletcher et al. 1992) (same study as (Vickerman 1992)) found that only one of 11 bird species declined in numbers with high pesticide inputs and none of four species had reduced breeding performance. The percentage of the total territories in the high input area for the 11 species remained fairly constant during the project (pre-treatment: 44-46%, treatment: 40-50%). Common starling Sturnus vulgaris showed a significant decline in percentage of breeding territories in the high input area relative to the low input area from 1984 to 1987 (45% to 28%), numbers recovered in 1988 (41%). There were no significant differences in breeding performance between treatment areas for tree sparrow Passer montanus or starling in terms of numbers of breeding pairs, numbers of young fledged, numbers of young fledged/pair or causes of nest losses. The only difference was that the percentage of first broods that failed to produce at least one fledgling tended to be lower in the high input area in baseline years, but increased more than the low input areas in treatment years. However, overall production of young was not reduced in the high input area. Sample sizes were small for blue tit Parus caeruleus and great tit P. major nests. Pre-treatment years were 1982-1983 and treatment years 1984-1988. The ‘Common Bird Census’ method was used to monitor birds, with 10 visits from spring to early summer. A total of 220-244 nest boxes were put up in each area, which were checked weekly during the breeding season.