Adult buzzard
Predatory Bird Monitoring Scheme (PBMS)

Science challenge

The Predatory Bird Monitoring Scheme (PBMS) provides long-term national monitoring and assessment of the risks to vertebrate wildlife from environmental contaminants. This includes understanding of how and why contamination varies over time and space.

The chemicals monitored by the PBMS are those commonly used in rodenticides, flame retardants and other manufacturing processes. Some of these chemicals persist in the environment and accumulate via the food chain to the organs of predatory species such as birds of prey and mammals.

Project summary

The PBMS is a citizen science programme. Members of the public send us carcasses of predatory birds such as owls, kestrels, sparrowhawks and red kites that are found dead. We analyse the concentrations of contaminants in these birds’ tissues, as well as in eggs sent to us by licenced collectors. We use this information to determine how and why contaminant concentrations vary between species and regions, how they are changing over time, and the effects that they may have on individual birds and their populations. We typically receive, catalogue, process, post-mortem and archive samples from 300-600 carcasses and over 100 eggs per year.

Data generated by the scheme contributes to the Natural Environment Research Council’s objective of increasing resilience to environmental hazards. Our findings are also used by governmental and non-governmental organisations to assess the risk that chemical contaminants pose to wildlife and potentially to human health, to develop our knowledge of the food-chain transfer and effects and to provide information on the need for, and the success of, mitigation measures. The PBMS contributes to wider national and international monitoring and risk assessment programmes and provides a scientific evidence base to inform regulatory decisions. For example, PBMS data are presented annually to the UK Government Oversight Group for Rodenticide Stewardship.


  • To provide a long-term, national scale monitoring programme of contaminants in the tissues of predatory birds
  • To make data and tissue samples available to a range of stakeholders, including researchers and decision-makers
  • To provide health indices for six core predatory bird species
  • To report on exposure to rodenticides by selected bird species
  • To lead on the development of a UK Environmental Specimen Bank.


Maps and indices

Sparrowhawk and bird submissions map screenshot

PBMS Bird Submissions Map The PBMS receives submissions of birds from throughout the UK. As part of the UK-SCAPE programme, we have developed a live interactive map displaying birds of prey received since 1990, so you can see the number and species of birds that we've received from different areas of the UK. For some sparrowhawk specimens, the map also shows concentrations of total PCBs (Polychlorinated biphenyls) in their livers. The latter is a proof of concept exercise and will be expanded to other data sets generated by the PBMS.


Barn owl and health indices graph screenshot

PBMS Bird Population Health Indices Each bird that is submitted to the PBMS is given a post-mortem examination during which me make approximately 60 macroscopic observations and measurements. We can use these observations to generate population health indices that can inform us about the status of recruitment and survival, physiological stress, and nutritional status in the population. Changes in these indices may indicate where the population is under stress and therefore highlight where we might focus our monitoring to determine if chemical exposure is contributing to the changes observed.



Videos: An overview of the PBMS and how to contribute to the PBMS.

Video: Contaminant-specific power analysis for the common buzzard for cost-effective monitoring - YouTube (presentation by Lee Walker at SETAC Europe, May 2022.

Research facilities

The PBMS operates two main facilities:

  1. a necropsy lab that facilitates post mortem examinations of predatory birds under Class 1 Biological Safety conditions
  2. A -18°C tissue archive containing tissues and egg contents from a range of predatory birds sine the 1960s.

Further information


Potentially part of a wider package for pesticide monitoring (along with the Honey Monitoring Archive) - this is currently being explored with Defra funding. PBMS provides a platform for wider NERC research and is a key component of the four-year ChemPop project, which began in September 2018 and is one of NERC's Chemicals in the Environment Programme funded grants.

Project lead - Lee Walker