White-eyed Vireos are unusual among North American mimics in that they put only other call notes, not songs, into their own songs. In his new book "Birdsong by the Seasons" Don Kroodsma recorded a male for 2 hours and came up with 16 mimicked call notes. Inspired by this, I decided to try the same.
On June 7th 2009 I observed and recorded a White-eyed Vireo for a little over two hours between 7.30 and 9.40 am at Glassboro Woods WMA, New Jersey. It sang 12 different songs, switching songs about every 10 minutes. After singing 12 different songs, it started singing some of its earlier songs again, at which point I left. These are the songs in the order in which they were sung:
Acadian Flycatcher first call, Carolina Wren scold, Blue Grosbeak (r-shaped call in the middle), American Robin cuck (faint inverted v, 3rd from end).
Wood Thrush whit whit, American Robin, probable Veery (Veery calls are very variable), Gray Catbird chuck (penultimate call).
Gray Catbird (faint 3rd call), Carolina Wren jeer at end. In the background you can hear a rival White-eyed Vireo singing a song that also has the jeer.
Brown Thrasher, Northern Flicker, Wood Thrush whit whit, single soft Wood Thrush alarm (the first five notes).
Red-bellied Woodpecker first call, immediately followed by Yellow Warbler/American Redstart-type chip, Gray Catbird; Carolina Chickadee at end.
Red-bellied Woodpecker (2nd call), single Wood Thrush soft alarm (in center), Gray Catbird chuck (penultimate call).
Wood Thrush soft alarm.
Hairy Woodpecker (2nd call), Gray Catbird (3rd call).
Gray Catbird (2nd call); Acadian Flycatcher and Wood Thrush soft call at end.
Wood Thrush whit whit, followed by Veery, Eastern Phoebe chip at end.
Red-eyed Vireo (whiny second call), American Robin (faint,center), Gray Catbird (faint,penultimate call).
Downy Woodpecker, Great Crested Flycatcher, Hairy Woodpecker; Wood Thrush soft alarm at end.
That's a total of 19 call notes of other species, and there may be a few others that I haven't put a name to.
The mimicked calls being used in the songs are alarm calls of other species breeding in the same habitat. I suspect the vireos learn at least some of the mimicked calls from other White-eyed Vireos, rather than picking up all the call notes on their own. Whatever they're doing, it's quite a game working out what's in their songs.