title: Going cheap: determinants of bird price in the Taiwanese pet market.
abstract: BACKGROUND
  International wildlife trade is the largest emerging source of vertebrate invasive alien species. In order to prevent invasions, it is essential to understand the mechanics of trade and, in particular, which traded species are most likely to be released or escape into the wild. A species' economic value is a key factor, because we expect cheaper species to be less assiduously secured against escaping, and more likely to be deliberately released. Here, we investigate determinants of the price of species in the Taiwanese bird trade. Taiwan is an international hub for bird trade, and several native species are threatened by alien bird species.
  
  
  METHODS
  We investigated the relationship between the traded species sale price in Taiwan and the species availability for trade (the number of birds for sale, geographic range size and their origin, conservation and CITES status) and traits (body size, coloration, song attractiveness). We used phylogenetic generalized least squares models, with multi-model inference, to assess the variables that are best related to the price of birds in the Taiwanese pet trade.
  
  
  CONCLUSIONS
  We found that species available for sale in larger numbers, native to Taiwan, not globally endangered, and small-bodied are all relatively cheaper, as too are species lacking yellow coloration and without attractive songs. Our models of price revealed high levels of phylogenetic correlation, and hence that closely related species tended to be sold for similar prices. We suggest that, on the basis of price, native species are more likely to be deliberately or accidentally released than alien species. Nevertheless, our survey of bird shops recorded 160 species alien to Taiwan (7,631 individuals), several of which are for sale cheaply and in large numbers. Alien bird species in trade therefore present an ongoing, non-trivial invasion risk on the island.
authors.affiliation: Institute of Zoology, Zoological Society of London, Regent's Park, London, United Kingdom; Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, United Kingdom; School of Biological Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: Shan
authors.initials: S
authors.lastname: Su
authors.affiliation: School of Biological Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: Phillip
authors.initials: P
authors.lastname: Cassey
authors.affiliation: School of Biological Sciences, University of Adelaide, Adelaide, Australia.
authors.forename: Miquel
authors.initials: M
authors.lastname: Vall-Llosera
authors.affiliation: Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, United Kingdom; School of Biological Sciences, University of Adelaide, Adelaide, Australia; Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: Tim M
authors.initials: TM
authors.lastname: Blackburn
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000033:anatomy & histology; D049628:Body Size; D003132:Commerce / Q000706:statistics & numerical data*; D003247:Conservation of Natural Resources; D058865:Introduced Species; D057805:Pets / Q000033:anatomy & histology / Q000191:economics*; D013624:Taiwan; D014828:Vocalization, Animal