Second generation anticoagulant rodenticides in predatory birds: probabilistic characterisation of toxic liver concentrations and implications for predatory bird populations in Canada

Thomas, Philippe J.; Mineau, Pierre; Shore, Richard F.; Champoux, Louise; Martin, Pamela A.; Wilson, Laurie K.; Fitzgerald, Guy; Elliott, John E.. 2011 Second generation anticoagulant rodenticides in predatory birds: probabilistic characterisation of toxic liver concentrations and implications for predatory bird populations in Canada. Environment International, 37 (5). 914-920. https://doi.org/10.1016/j.envint.2011.03.010

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Official URL: http://dx.doi.org/10.1016/j.envint.2011.03.010

Abstract/Summary

Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent pests but exposure and poisonings occur in non-target species, such as birds of prey. Liver residues are often analysed to detect exposure in birds found dead but their use to assess toxicity of SGARs is problematic. We analysed published data on hepatic rodenticide residues and associated symptoms of anticoagulant poisoning from 270 birds of prey using logistic regression to estimate the probability of toxicosis associated with different liver SGAR residues. We also evaluated exposure to SGARs on a national level in Canada by analysing 196 livers from great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) found dead at locations across the country. Analysis of a broader sample of raptor species from Quebec also helped define the taxonomic breadth of contamination. Calculated probability curves suggest significant species differences in sensitivity to SGARs and significant likelihood of toxicosis below previously suggested concentrations of concern (< 0.1 mg/kg). Analysis of birds from Quebec showed that a broad range of raptor species are exposed to SGARs, indicating that generalised terrestrial food chains could be contaminated in the vicinity of the sampled areas. Of the two species for which we had samples from across Canada, great horned owls are exposed to SGARs to a greater extent than red-tailed hawks and the liver residue levels were also higher. Using our probability estimates of effect, we estimate that a minimum of 11% of the sampled great horned owl population is at risk of being directly killed by SGARs. This is the first time the potential mortality impact of SGARs on a raptor population has been estimated.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.envint.2011.03.010
Programmes:	CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 1 - Monitoring and Interpretation of Biogeochemical and Climate Changes
UKCEH and CEH Sections/Science Areas:	Shore
ISSN:	0160-4120
Additional Information. Not used in RCUK Gateway to Research.:	There is a corrigendum to this paper in Environment International 40 (2012) 256 - click on Related URL link for details
Additional Keywords:	rodent, exposure, liver residues, toxicity threshold, anticoagulant rodenticide
NORA Subject Terms:	Zoology Ecology and Environment
Related URLs:	Other
Date made live:	17 May 2011 10:11 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/14168

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.envint.2011.03.010

Programmes:

CEH Topics & Objectives 2009 - 2012 > Biogeochemistry > BGC Topic 1 - Monitoring and Interpretation of Biogeochemical and Climate Changes

UKCEH and CEH Sections/Science Areas:

Shore

ISSN:

0160-4120

Additional Information. Not used in RCUK Gateway to Research.:

There is a corrigendum to this paper in Environment International 40 (2012) 256 - click on Related URL link for details