Seems to me that any species that competes with another on any basis would be well
served to come up with territorial defenses like mimic songs. If you accept the premise
that these two species do compete (not a given, but would seem likely in this case),
then the reasons for a wren singing a sparrow song are not much different from a sparrow
singing a sparrow song, i.e. "stay offa this turf, I want it all to myself."

If live wrens don't fare much better than mounted ones in a confrontation with a song
sparrow, then it might be wise not to tangle with a sparrow already on territory. But if
the wren were to start singing in an unoccupied territory, it might fool arriving sparrows
into moving along to the next territory, in which case it might make all the sense in the world.

It would be interesting to know whether or not female Bewick's wrens would be impressed...

Jim McCoy
Redmond, WA
jfmccoy at earthlink.net


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Dennis Paulson (excerpted):
>Vis-a-vis your comments on tweeters about Song Sparrow and Bewick's Wren
>song convergence and possible mimicry ... He used tapes and mounted specimens
>of both and had SOSP come
>and wallop the hell out of "singing" BEWR with a high statistical
>significance (i.e., somewhere near the frequency with which they showed
>the same response to "intruding" SOSP).

Michael Price (excerpted):
Off the top of the head, Dennis, the question arises: why would the wrens
devise mimic-songs if a good bashing from an enraged sparrow is the reward?
...