More pesticide impacts on birds 

Yellowhammers and skylarks can be added to the list of British birds affected by pesticides. A recent study by the Royal Society for Protection of Birds (RSPB) finds evidence that the use of pesticides on farmland may be contributing to declines in both these species. 

Populations of many wild animals have been declining in the UK over the past half-century. These declines are best documented in birds mainly due to their high visibility and popularity with the British public. Surveys coordinated by the British Trust for Ornithology have reliably documented annual distributions allowing overall trends to be observed. These trends have highlighted the stark plight faced by our farmland birds, many of which have undergone remarkable declines in the past few decades. A 1997 publication reported population declines in 24 out of 40 farmland species with declines as severe as 80% for certain birds including the tree sparrow, grey partridge, corn bunting and bull finches(1). 
    Organochlorine pesticides, such as DDT, have directly impacted populations of some birds of prey. In addition to these direct impacts on the viability of bird populations pesticides indirectly impact birds through removal of their food sources. This is well documented for both the grey partridge and the corn bunting. Now new research carried out by the RSPB finds that yellowhammers and skylarks are also adversely affected by pesticides. 
    Yellowhammers were observed on lowland farms between1995 and 2001. Results of the study showed that adult yellowhammers feeding their offspring did not forage in fields sprayed with insecticide. In addition offspring from nests next to sprayed fields were in poorer condition than those from nests next to unsprayed fields(2). Similar results were observed for skylarks but the sample size was smaller and consequently results less robust.
    Britain currently uses more than twice the average amount of pesticides than any other OECD (Organisation for Economic Cooperation and Development) country(3). Conservation of our native wildlife is just one of many reasons why the UK needs to adopt a pesticide use reduction policy. (RM)

References
1. Campbell, L.H. and Cooke, A.S. (eds), The indirect effect of pesticides on birds, Joint Nature Conservation Committee, 1997.
2. Morris, A.J. and Bradbury, R.B, Indirect effects of pesticides on breeding yellowhammers Emberiza citrinella Proceedings of the British Crop Protection Council Pest and Disease Conference, Brighton, 2002.
3. Environmental Performance Reviews – United Kingdom, Organisation for Economic Cooperation and Development, 2002.

[This article first appeared in Pesticides News No. 59, March 2003, page 17]