Judging from the very few daring guesses, this was a real tough sound quiz.
As I mentioned in last week’s post, I was quite surprised when I looked up to see that this nearly ultrasonic song was being given by a Rufous-breasted Wren, Pheugopedius rutilus. As a reminder, here is the song from last week:
[iframe http://www.xeno-canto.org/embed.php?XC=97451&simple=0 340 230]
And here is a more typical song, recorded earlier the same day, also at Carara National Park, Costa Rica:
[iframe http://www.xeno-canto.org/embed.php?XC=97850&simple=1 340 160]
And look at the sonogram – there is no overlap in frequencies between the two song types.
Of course, the questions I’d like answered are: What does this odd song type mean? Is it given frequently? Or is it an aberration? Wrens aren’t known to mimic (with the exception of the outlying genus Odontorchilus), so the one suggestion that this might be an imitation of Gray-crowned Yellowthroat probably isn’t the answer (and I don’t think Rufous-breasted Wrens often get a chance to hear them anyway.)
Anyway, here are a few more photos of some of the Carara National Park specialties that one might see on the same trail where Rufous-breasted Wrens are common.