Earbirding

It’s a commonly held conception that only male birds sing.  And for many birds in North America that is indeed the case.  However, there are cases of female birds that sing as well – finches, orioles, cardinals, and some warblers (occasionally), among others.  In North American wrens, for the most part, only the males sing, but  exceptions include House Wren, Cactus Wren, AND Canyon Wren.

This is in sharp contrast to tropical wrens, who have among the best female singers in the entire avian world.  Indeed, the duets of some of the South American wrens are probably some of the all time great bird sounds on the planet!  Take a listen to these two different subspecies of Plain-tailed Wren: XC42098 and XC58882.

Back up here in North America, the song of male Canyon Wren is among the best known (and most beautiful) of the sounds in the west, echoing off canyon walls just about anywhere with appropriate habitat – take a listen below.

But Birds of North America gives an interesting tidbit if you dig a bit further: “Both sexes sing, but female song is rarer and usually shorter.”  It goes on to describe a couple of female vocalizations, but without spectrograms and without a whole lot of detail.  So it is up to the observer to figure out what female song is when in the field.  A while back Nathan told me about this vocalization, and gave me a recording he made in Arizona that he thought was the female song, asking me to keep an ear out for it and to try to get a better recording.  I was intrigued – there’s little I love more than a bird sound mystery – so I edited the recording for playback and put it onto my i-pod (you can also hear another example at 46 seconds on LNS#21482).

A few weeks later I had my first chance.  I was in Irish Canyon in far northwestern Colorado, and I heard the liquid notes of a Canyon Wren song on a nearby cliff.  I walked over, and played the tape in the middle of the bird singing.  I was a bit startled at what happened next – the singing bird stopped, mid-strophe, and flew right in at me, calling loudly and angrily.  It was also giving an unusual call type (see below), and continued giving it for some time, from the middle of pinyon pine trees and on the ground.  Eventually it flew up to the top of a tree and started singing again, but still reacted the same way the next time I played Nathan’s recording. What it did not do, nor did any other bird in the area do, was sing the “female” song that I had on my i-pod.

I took this as something of a challenge.  That morning I played to three more singing Canyon Wrens.  All reacted to the track, though none as strongly as the first bird, but none responded with the same vocalization as the one on the tape.

Finally, about a week later, I hit pay dirt.  This time I was down near the town of Dinosaur, and I randomly played Nathan’s cut just to see what would happen.  I didn’t hear a response, and after waiting a couple of minutes I began to walk away.  Then there it was!  High up on the cliff was a perfect carbon copy of what I had just played.  I got a witness recording, and began to move in.  I was soon watching the bird as it sang from on top of prominent rocks, and after another quick playback, on some nearby tall shrubs.  To hear for yourself what it sounds like, take a listen to the cut below:

When I played the recording I had gotten to the bird in question it would react immediately and aggressively, flying in very close and giving the same vocalization back.  Interestingly, when I played back the normal song, it would barely react, at most just sitting up and looking around briefly.  Frustratingly, I was unable to ever confirm two birds at once, so I can’t say for sure that this is from a female bird.  However, about half an hour later there was a bird in the same territory singing the normal song, and when I played back the “female” song to that individual it didn’t react much at all, and the one time it did it came in low giving the same calls as the bird from Irish Canyon.  When I played the normal song back to it, though, it went ballistic, flying right in and singing at close range.

I also took photos of both birds, and examining these later I could see what I believe are differences between the two.  SO there seems to be a preponderance of evidence for there being two birds in the same territory.  And since one of those birds was singing normal song and acting in a territorial manner (and is thus, presumably, a male), it would stand to reason that the bird I recorded singing “female” song was, in fact a female.  But I can’t be certain, so I guess I’ll have to keep trying!