Figure 2

Four of the six barn swallow subspecies. A) nominate European H. r. rustica, with pale ventral coloration and long tail streamers B) East Asian H. r. gutturalis, with pale ventral coloration and short streamers; C) Baikal region H. r. tytleri with very dark ventral coloration and intermediate streamers; and D) North American H. r. erythrogaster with dark ventral color and short streamers. Note that tytleri is much more similar in coloration to erythrogaster than to the geographically proximate Eurasian subspecies, supporting phylogenetic data that suggest it has re-colonized Asia from a North American ancestor. Photos courtesy of M. Wilkins.