Case of Emaciation in a Red Kite (Milvus milvus) – A Plastic Problem?

Abstract

In the UK, a total of 326 red kites (Milvus milvus) were released between 1989 and 2006 as part of a reintroduction program which has now increased the number of breeding pairs to an estimated 3000 across the UK (Molenaar et al., 2017). A vital aspect of their conservation has been post-release monitoring through post mortem examinations (PMEs) undertaken by the Disease Risk Analysis and Health Surveillance program (DRAHS) at the Institute of Zoology, Zoological Society of London (ZSL). A number of causes of death have been reported with some of the most common being anthropogenic in origin, including anticoagulant rodenticide poisoning and trauma (Carter, 2007).

This poster presents the case of a red kite found alive close to a human settlement. The bird was severely emaciated with evidence of trauma. It died within hours and was submitted to DRAHS for PME. No single cause of death was identified, but a large piece of hard, white coloured plastic was found in the ventriculus which may have contributed to the emaciation through hindering normal digestion. Anti-coagulant rodenticide poisoning was also considered a possibility due to pallor of the organs (results pending), and either of these underlying issues may have predisposed the bird to weakness and therefore trauma.

Plastic has been documented as a risk to numerous bird species across the world is widely considered to be a significant threat to their conservation and welfare (Lavers et al., 2013; Verlis et al., 2013; Wilcox et al., 2015). Scavenging species such as the red kite are likely to be at particular risk of ingestion of non-food items as they have been reported to feed close to human settlements increasing their likelihood of exposure (Ntampakis & Carter, 2005). Moreover, this plastic was remarkably similar in appearance to bone; birds of prey ingest bone to aid in calcium regulation, and thus this bird may have eaten the plastic mistaking it for a bone fragment (Houston et al., 2007).

This case highlights the growing anthropogenic threats faced by British wildlife in an increasingly urbanised environment and in particular the welfare implications of these threats. The conservation impact of anti-coagulant rodenticides is accepted, although further research is required to decipher whether plastic is a conservation threat to this species.

Full text

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!1  
!#/   %!!  
??Gymnogyps californianus)<(%Cathartes aura#!
  "!"((  
 ""#
/!1   ! !(  %
 (  !!#
 !"!-  "!"#/!
 !!   (" 
"  #%% "!
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