Location of Repository

Anticoagulant rodenticides in predatory birds 2009: a Predatory Bird Monitoring Scheme (PBMS) report.

By L.A. Walker, N.R. Llewellyn, M.G. Pereira, E.D. Potter, A.W. Sainsbury and R.F. Shore

Abstract

The Predatory Bird Monitoring Scheme (PBMS; http://pbms.ceh.ac.uk/) is the umbrella project that encompasses the Centre for Ecology & Hydrology’s National Capability contaminant monitoring and surveillance work on avian predators. By monitoring sentinel vertebrate species, the PBMS aims to detect and quantify current and emerging chemical threats to the environment and in particular to vertebrate wildlife.\ud Anticoagulant rodenticides, and in particular second generation anticoagulant rodenticides (SGARs), can be toxic to all mammals and birds. Predators that feed upon rodents are particularly likely to be exposed to these compounds. The PBMS, together with other studies, have shown that there is widespread exposure to SGARs of a diverse range of predators in Britain and that some mortalities occur as a result. This report summarises the PBMS monitoring for anticoagulant rodenticides in barn owls (Tyto alba), and red kites (Milvus milvus) that were found dead in 2009 and presents long term trend analysis for barn owls.\ud Since 2006, anticoagulant rodenticide concentrations have been quantified using the more sensitive Liquid Chromatography – Mass Spectrometry (LC-MS) method. This has resulted in lower concentrations of these compounds being detected than was previously possible. Consequently, for samples from 2006 onwards, the proportion of birds in which anticoagulant rodenticides have been detected has increased compared to previous years.\ud SGARs were detected in 89% of barn owls and the most prevalent compounds were difenacoum and bromadiolone. The majority of the residues were low and not diagnosed as directly causing mortality. Only five red kites were received by the scheme in 2009. Most of the red kites (4 o/5 birds) had detectable liver SGAR concentrations, again mainly difenacoum and bromadiolone although brodifacoum was also detected in over half the birds. Two of the five red kites analysed showed signs of haemorrhaging thought possibly to be associated with rodenticide poisoning.\ud SGARs have been monitored in barn owls since 1983. Data on long-term trends have been adjusted to account for changes over time in sensitivity of analytical methods. This has meant that very low residues (<0.025µg/g wet weight), which are now easily detectable, are not included in the time trend analysis. The proportion of owls with detectable SGAR residues was found to be two-fold higher in England than in either Scotland or Wales. Overall, the proportion of barn owls with detectable liver concentrations of one or more SGAR has increased significantly over the course of monitoring. The highest value was recorded in 2008 but this was approximately twice that for the previous three years. The value for 2009 was lower than 2008 but remains one of the highest recorded since monitoring began. \ud Continued monitoring is required to determine whether the high detection rate for SGARs in barn owls in 2008 and 2009 will change. Although our data for red kites in 2009 is limited, it is consistent with a high proportion of red kites being exposed to SGARs and some dying as a result. This species remains at particular risk from anticoagulant rodenticides.\u

Topics: Ecology and Environment
Publisher: NERC/Centre for Ecology & Hydrology
Year: 2010
OAI identifier: oai:nora.nerc.ac.uk:12976

Suggested articles

Preview

Citations

  1. (2010). Accumulation of anticoagulant rodenticides in a non-target insectivore, the European hedgehog (Erinaceus europaeus).
  2. (2003). Agricultural pesticides and mammals in Britain. Conservation and conflict: mammals and farming in Britain.
  3. (2010). Anticoagulant rodenticides in predatory birds
  4. (2006). Did Foot and Mouth Disease control operations affect rodenticide exposure in raptors? doi
  5. (1999). Empirical evidence of side-effects of rodenticides on some predatory birds and mammals.
  6. (2002). Report No. 451: The Red Kite Reintroduction Programme in England.
  7. (2001). Rodenticide residues in the kestrel Falco tinnunculus.
  8. (1990). Rodenticides in British Barn Owls.
  9. (2008). Second generation anticoagulant rodenticides in tawny owls (Strix aluco) from Great Britain. doi
  10. (2003). Spatial and temporal analysis of second-generation rodenticide residues in polecats (Mustela putorius) from throughout their range in Britain,
  11. (2010). The Predatory Bird Monitoring Scheme (PBMS) Report 2006-7. A contract report from the Centre for Ecology & Hydrology to Natural England, Centre for Ecology & Hydrology,
  12. (2008). The Predatory Bird Monitoring Scheme: Identifying chemical risks to top predators in Britain. doi
  13. (1998). Wildlife and Pollution: 1997/98. Annual Report.

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.