Stable hydrogen isotope analysis as a method to identify illegally trapped songbirds Andrew Kelly a,b, ⁎ , Richard Thompson c , Jason Newton d a IBLS, Division of Environmental and Evolutionary Biology, Graham Kerr Building, University of Glasgow G12 8QQ, UK b RSPCA Stapeley Grange Wildlife Centre, London Rd., Stapeley, Nantwich, Cheshire CW5 7JW, UK c RSPCA Mallydams Wood Study and Wildlife Centre, Peter James Lane, Fairlight, Hastings, TN35 4AH, UK d NERC Life Sciences Mass Spectrometry Facility, Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, UK Accepted 25 September 2007 Abstract We measured stable hydrogen isotope ratios in the primary feathers of two subspecies of goldfinches, confiscated by the Police and the Royal Society for the Prevention of Cruelty to Animals (RSPCA) on suspicion that they had been illegally taken from the wild. We found significant differences in the δ 2 H values of the two subspecies indicating that they were sourced from different geographical regions. Our results correlated with isotopic precipitation maps and with the known distribution of the two subspecies of goldfinch. We believe that this technique could be used by law enforcement agencies to determine the origin of birds in cases where the species or subspecies involved are geographically distinct. © 2007 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved. Keywords: Stable isotopes; Hydrogen; Deuterium; Goldfinch; Carduelis carduelis; RSPCA 1. Introduction Thousands of wild songbirds are illegally trapped across Europe each year and many are illegally imported into the UK destined for a lucrative market where a wild finch can fetch around £40 Sterling. Conversely, birds trapped in the UK are often illegally exported to markets across southern Europe, particularly Malta. Between 2001 and 2006, there were 248 cases involving the illegal taking, possession or sale of wild birds (not including birds of prey) recorded by the Royal Society for the Protection of Birds (RSPB) [1]. Although there was a welcome decrease in the number of cases between 2001 and 2004 from 51 to 23, in 2006 there were 66 cases recorded by the RSPB involving an unknown number of birds, mainly goldfinches (Carduelis carduelis), bullfinches (Pyrrhula pyrrhula) and chaffinches (Fringilla coelebs). Many of these cases were investigated by the Special Operations Unit of the Royal Society for the Prevention of Cruelty to Animals (RSPCA). In 2006, the RSPCA brought 12 successful prosecutions against individuals for the illegal taking or possession of songbirds (mostly finches) and equipment used for trapping birds. One of the main problems facing investigators of these alleged crimes is providing evidence that the birds were not captive bred. Currently, birds suspected of having been trapped illegally in the wild are examined by an expert witness who uses feather wear as an indication of age and origin. However, although these witnesses are very skilled, the evidence is often questioned as being rather subjective and those accused of offences often find equally skilled expert witnesses to refute the prosecution witness testimony. The authorities and the NGOs involved in the battle against illegal trapping and possession of wild birds would welcome a more objective line of evidence. In the 1990s, there were a number of high profile cases in which DNA evidence extracted from birds of prey was used to challenge captive breeding claims. Also for birds of prey, the introduction of a registration scheme for captive bred birds made it more difficult for wild caught birds to be passed off as captive bred birds. However, for small songbirds, such as Available online at www.sciencedirect.com Science and Justice 48 (2008) 67 – 70 ⁎ Corresponding author. RSPCA Stapeley Grange Wildlife Centre, London Rd., Stapeley, Nantwich, Cheshire CW5 7JW, UK. Tel: +44 (0)1270 628755, fax: +44 (0)1270 610385. E-mail address: ankelly@RSPCA.org.uk (A. Kelly). 1355-0306/$ - see front matter © 2007 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.scijus.2007.09.012