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Research article - Peer-reviewed, 2021

Annual abundance of common Kestrels (Falco tinnunculus) is negatively associated with second generation anticoagulant rodenticides

Roos, Staffan; Campbell, Steve T.; Hartley, Gill; Shore, Richard F.; Walker, Lee A.; Wilson, Jeremy D.

Abstract

Rats and mice can damage food and agricultural products as well as transmit diseases, thereby requiring control of their numbers. Application of Second Generation Anticoagulant Rodenticides (SGARs) often reduces rodent numbers locally. However, predators eating rodents, including non-target species, that have consumed SGARs may be secondarily exposed and potentially lethally poisoned. Here we study whether SGARs may have contributed to the widespread population declines of a rodent-eating raptor, the Common Kestrel (Falco tinnunculus) in the UK. We show that 161 (66.8%) of the 241 Kestrels submitted for ecotoxicology tests between 1997 and 2012 had detectable levels of at least one SGAR in their livers. Adult Kestrels had significantly higher prevalence of SGARs than juveniles, suggesting accumulation of SGARs through time. The prevalence and concentrations of individual SGARs in Kestrels were significantly higher in England than in Scotland. SGAR prevalence in Kestrels were positively associated with some land cover types, primarily arable cereals and broad-leaved woodland, and negatively associated with mainly mean elevation, probably reflecting variation in SGAR usage across land cover types. By using volunteer-collected data on national Kestrel abundance 1997-2012, we show that there is a negative correlation between the Kestrel population index in a specific year and the concentration of bromadialone as well as the total SGAR concentration in the same year. Although correlative, this is the first study to provide evidence for a potential population-limiting effect of SGARs on a raptor.

Keywords

SGAR; Raptors; Poisoning; Sub-lethal effects; Birds of prey; Breeding Bird Survey

Published in

Ecotoxicology
2021, volume: 30, number: 4, pages: 560-574
Publisher: SPRINGER

Authors' information

Swedish University of Agricultural Sciences, Swedish Species Information Centre
RSPB Centre for Conservation Science
Campbell, Steve T.
Science and Advice for Scottish Agriculture (SASA)
Hartley, Gill
Science and Advice for Scottish Agriculture (SASA)
Shore, Richard F.
UK Centre for Ecology and Hydrology (UKCEH)
Walker, Lee A.
UK Centre for Ecology and Hydrology (UKCEH)
Wilson, Jeremy D.
Royal Society for Protection of Birds

UKÄ Subject classification

Ecology

Publication Identifiers

DOI: https://doi.org/10.1007/s10646-021-02374-w

URI (permanent link to this page)

https://res.slu.se/id/publ/111485