Monday, October 14, 2013
The Singer is Revealed at Last!
I’ve been trying to track down a singing Broad-winged Tree Cricket for the past two years. I knew the song was a loud, continuous trill. There are other crickets in the meadows and tangled, brushy edge habitats with loud continuous trills, though, and I hear them every time I go out in the field from early August until frost. How is the Broad-winged Tree Cricket different from the Black-horned and Four-spotted Tree Crickets I hear all the time?
I have read that they have fewer wing strokes per second and they are even louder than the other two species. But I wanted to know how to tell in the field in real time which species was singing! Practicing was not going to be easy, either. I suspected that they mature later than the others – possibly not until September – and I couldn’t actually find them to confirm the singer and the song. They also don’t seem to be so common in the areas around Cleveland. Carl Strang is tracking their northward movement in the Chicago area, and you can read about his research here: They may be moving north in our region as well, but I can’t begin to determine this until I know where they are right now.
I had seen one Broad-winged Tree Cricket at Pond Brook Conservation Area in Summit County a few years ago, but he wasn’t singing. No luck at all last year, and then this year I saw a mating pair at the Nature Realm in Summit County.
They weren’t singing at the time (they were otherwise engaged), but I heard a few songs that seemed lower in pitch than the other tree crickets. These songs seemed to come from no more than a few feet above the ground underneath dense blackberry tangles in a meadow area.
Of course, if I got anywhere near, they promptly stopped singing.
But at least I began to develop a plan. My suspected Broad-winged Tree Crickets consistently sang a little lower in pitch than the Black-horned and Four-spotteds. For you musicians, that interval was consistently a minor third lower – sometimes maybe a major third. I began to notice this intervallic relationship in other areas as well. I was pretty sure I had this figured out, but I would have to actually find one of the singers to be convinced.
Easier said than done, of course, and the singing insect season was rapidly coming to a close…
On October 9th, I was investigating Frohring Meadows in the Geauga Park District for Texas Bush Katydids and Round-tipped Coneheads. I heard crickets singing a minor third lower in a couple of places with dense vegetation that I had no hope of penetrating without causing a huge song-stopping disruption. Of course, this just made me all the more determined. I had looked for them a couple of weeks earlier and had gone into a wetland tangle so dense that I could barely move, but this time I just had to find them. After all, it was already October 9th!
I followed my microphone into a typically dense blackberry tangle at the edge of the same wetland area. Instead of a diffuse loud, rich song, I was getting a clearer sense of direction than was usually the case. I was SO CLOSE!
Then I saw an antenna, and then…
A raspberry red cap and antenna base! Yes! But this wasn’t the male – it was a female. She was larger than I expected – not quite as large as a Two-spotted Tree Cricket, but certainly more substantial than either a Black-horned or Four-spotted Tree Cricket. She was very pale, too, with a strikingly dark ovipositor.
Now where was the male? This was where my microphone said the song had been located. I thought I saw the tips of two antennae, and I slowly, gently turned over a blackberry leaf…
Aha! I had found the very singer who made the song I’d just recorded!
Their color blends in with the blackberry leaves and the other colors of the autumn meadow. Add to that their preference to stay on the underside of leaves and close to the ground in prickly tangles, and it’s no wonder they are hard to find.
Now look at that antenna base and the top of the head – no other cricket in our area has this gorgeous color pattern.
My pitch relationship identification had worked well for me. Different recordings of the same species can sound like different crickets because their songs will be higher in warm temperatures and lower when the temperature drops. However, the other species’ songs will rise and fall with the temperature, so it seemed possible that a pitch correlation between species might exist whether the temperature is 78 degrees or 63 degrees (the temperature for the second recording in this blog entry). I’ve documented this relationship in the appropriate habitat at other locations, and I think I just may have the answer key for my search. Music theory meets natural history once again!