After listening carefully to Pine Siskins this year to pick out the calls of other species (see my earlier post) I have run across several other mimics. In early June in Arlington, Massachusetts I heard a remarkable American Goldfinch song that incorporated several phrases of a Song Sparrow song along with Northern Flicker and I suspect other species were being copied but I couldn’t pick them out. This is the first time I’ve heard an American Goldfinch that included copies of other species in its song, and these were very clear and obvious copies, but as Dan Lane pointed out in comments on my previous Siskin post American Goldfinch seems to be exceptional – the one American member of the genus that does not copy. Apparently they do, at least occasionally.
In western Massachusetts in late June 2009 I heard a male Purple Finch giving its territorial song. This territorial song began with a bright warble like a typical Purple Finch song, then continued into a longer and more varied section – a jumble of short song phrases and copies of other species. I was able to pick out copies of American Robin, Tufted Titmouse, Eastern Towhee, and Hairy Woodpecker, and again I suspect there were more. In this case the copying has been previously reported in the literature, with the BNA account mentioning Barn Swallow, American Goldfinch, Eastern Towhee, and Brown-headed Cowbird.
Several years ago I noticed a few copies in the flight song of an Ovenbird, and I’ve heard a few others since then. Over several days in late June 2009 I was able to hear many flight songs from one Ovenbird in Colton, New York, which included copies of Red-eyed Vireo song phrase, Robin tut note, and a Purple Finch song phrase. There are very few recordings of the flight song (since it is given at such long intervals) but one on the Stokes Guide to Bird Songs: Eastern includes a lot of mimicry. Listening carefully to that I can hear a snippet of Winter Wren song, the trill of Eastern Towhee song, Red-eyed Vireo song phrase, and ending with White-eyed Vireo song. It’s such a jumble of calls that (like the Siskin song) it’s very hard to pull out all the copies, so I suspect there are others, and this whole performance – other than the few typical Ovenbird song phrases in the middle – might be copies. This is another instance of vocal copying that has never been reported before, as far as I know. The BNA account for Ovenbird makes no mention of it.
It’s interesting that both the Purple Finch and Ovenbird use copies in these sort of extended or auxiliary songs, and not in the more frequently heard “typical” songs.
I should point out a very interesting new blog by Nathan Pieplow about bird vocalizations, with a comment on the Pine Siskin issue here, and lots of other good stuff. And another blog about bird voices by Paul Driver, with a recent post about Mimicry here.
McGraw, Kevin J. and Alex L. Middleton. 2009. American Goldfinch (Carduelis tristis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/080
Van Horn, M. A. and T.M. Donovan. 1994. Ovenbird (Seiurus aurocapilla), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/088
Wootton, J. Timothy. 1996. Purple Finch (Carpodacus purpureus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/208