Table 1. Mean K2P pairwise distances between species in parapatric species pairs in three genes, cox1, cob, and 16S. species pairs Parapatric species pairs that do hybridise Acrocephalus stentoreus/Acrocephalus arundinaceus Alectoris chukar/Alectoris rufa Alectoris graeca/Alectoris chukar Alectoris magna/Alectoris chukar Anthus pratensis/Anthus spinoletta Anthus spinoletta/Anthus pratensis Aquila pomarina/Aquila clanga Archilochus alexandri/Archilochus colubris Callipepla californica/Callipepla gambelii Campylorhynchus zonatus/Campylorhynchus albobrunnea Carpodacus cassinii/Carpodacus purpureus Chrysolophus pictus/Chrysolophus amherstiae Contopus sordidulus/Contopus virens Contopus virens/Contopus sordidulus Coturnix japonica/Coturnix coturnix Crossoptilon auritum/Crossoptilon crossoptilon Delichon urbicum/Delichon dasypus Dendrocopos major/Dendrocopos syriacus Dendroica occidentalis/Dendroica townsendi Emberiza melanocephala/Emberiza bruniceps Eremophila bilopha/Eremophila alpestris Galerida theklae/Galerida cristata Gallus gallus/Gallus sonneratii Gavia immer/Gavia adamsii Hippolais polyglotta/Hippolais icterina Lanius collurio / Lanius isabellinus Lanius collurio/Lanius cristatus Lanius isabellinus/Lanius cristatus Lanius isabellinus/Lanius vittatus Lanius schach/Lanius tephronothus Lanius vittatus/Lanius collurioides Larus glaucoides/Larus thayeri Larus argentatus/Larus cachinnans Leucopternis melanops/Leucopternis kuhli Lophura nycthemera/Lophura leucomelanos Luscinia megarhynchos/Luscinia luscinia Melanerpes aurifrons/Melanerpes carolinus Melanerpes aurifrons/Melanerpes uropygialis Oenanthe hispanica/Oenanthe pleschanka Passer indicus/Passer domesticus Passerina amoena/Passerina cyanea Pheucticus ludovicianus/Pheucticus melanocephalus Phylloscopus sindianus/Phylloscopus collybita Phylloscopus sibilatrix/Phylloscopus bonelli Picoides nuttallii/Picoides scalaris Piranga ludoviciana/Piranga bidentata Plegadis falcinellus/Plegadis chihi K2P distances cox1 cob 16s 3.6 1.6 2.1 5.8 11.1 4.1 0.4 6.5 4.2 2.1 0.6 2.4 0.1 0.3 5.1 4.5 6 0.1 9.4 5.1 7.2 7.4 1.4 0.9 5.5 5 5 5 5 2.7 4 2 2.3 3 8.5 7.9 3 7 1 9 8.2 8 6 0.8 2 3 7.7 4 9.3 9 4.8 1.7 3 1.2 0.6 0.6 2.6 1.2 1.2 1.7 0.1 0.8 1 0.5 2.2 2.3 Table 1. cont. species pairs Pluvialis dominica/Pluvialis fulva Poecile carolinensis/Poecile atricapillus Poephila cincta/Poephila acuticauda Polioptila californica/Polioptila melanura Selasphorus rufus/Selasphorus sasin Sialia sialis/Sialia currucoides Sphyrapicus ruber/Sphyrapicus varius Streptopelia vinacea/Streptopelia capicola Sturnus unicolor/Sturnus vulgaris Tragopan blythii/Tragopan temminckii Turdus ruficollis/Turdus naumanni Vireo cassinii/Vireo solitarius Parapatric species pairs that do not hybridise Alectoris philbyi/Alectoris melanocephala Anthus spinoletta/Anthus rubescens Campyloramphus trochilirostris/Campyloramphus procurvoides Circaetus cinerascens/Circaetus fasciolatus Corythaixoides concolor/Corythaixoides personata Crax globulosa/Crax alector Crax rubra/Crax alberti Crinifer piscator/Crinifer zonurus Emberiza caesia/Emberiza hortolana Emberiza hortulana/Emberiza buchanani Gavia arctica/Gavia pacifica Geospiza difficilis/Geospiza fuliginosa Hippolais olivetorum/Hippolais languida Hirundo aethiopica/Hirundo lucida Hirundo albigularis/Hirundo angolensis Hirundo nigrita/Hirundo smithii Locustella lanceolata/Locustella fluviatilis Melanocorypha calandra/Melanocorypha bimaculata Melithreptus albogularis/Melithreptus lunatus Motacilla alba/Motacilla madaraspatensis Musophaga violacea/Musophaga rossae Parus xanthogenys/Parus spilonotus Ramphastos brevis/Ramphastos vitellinus Selenidera reinwardtii/Selenidera gouldii Sitta neumayer/Sitta tephronota Streptopelia orientalis/Streptopelia turtur Sylvia mystacea/Sylvia melanocephala Syrmaticus reevesi/Syrmaticus ellioti Tragopan satyra/Tragopan blythii Tragopan temminckii/Tragopan satyra Trogon melanurus/Trogon comptus Turdus pallidus/Turdus obscurus Veniliornis cassini/Veniliornis affinis Zosterops senegalensis/Zosterops pallidus doi:10.1371/journal.pone.0004119.t001 DNA Barcoding in Birds K2P distances cox1 cob 16s 4.8 2 2.4 2.8 2.1 5 5 5.8 4.7 9.9 0.9 9.8 5.7 6.7 6 3 2 7 3 7 4 6 4 5 5 9 2 9 9 11 10 5.9 6 5 3.9 5 5 5 8.5 6 7 8 2 5 0.5 0 0.1 1.2 1 2.7 1.3 1.1 2.3 PLoS ONE | www.plosone.org 5 January 2009 | Volume 4 | Issue 1 | e4119