The Wildllife Incident Investigation Scheme (WIIS) investigates potential pesticide poisoning incidents in the United Kingdom.

Incidents in England are investigated by Natural England and in Scotland by Science and Advice for Scottish Agriculture (SASA). In Wales the scheme is run by the Welsh Assembly Government and in Northern Ireland by the Department of Agriculture and Rural Development.

An initial telephone interview with a Wildlife Officer is used to record the evidence and concerns. If the Wildlife Officer suspects that pesticides are involved and the incident is within the WIIS remit, the Officer will arrange for the site to be inspected and the carcase and/or poison samples to be collected for analysis.

Further action, including prosecution, depends on the findings of the investigation.

Findings from WIIS investigations are published quarterly and an annual report is published which collates these reports is also published. The most recent annual (2007) summary of the Wildlife Incident Investigation Scheme has been published here. Maps showing the regional distribution and type of incident can be seen here. Quarterly reports showing incidents under investigation during 2009 can found here.