Thursday, July 24, 2014

"Did I hear a katydid back there?"

I’ve waited a long time to hear crickets and katydids again, and the concert is slowly beginning.  Spring Field Crickets really do sing in the late spring and into early summer, but they’re nowhere near as common as Fall Field Crickets around here and I don’t hear them too often.  Roesel’s Katydids began their electrical buzzing down in the meadow grasses in June, followed by my beloved Gladiator Meadow Katydids in the first days of July. (I wrote about the Gladiators last year and you can read that blog entry here.)

I never know how soon I’ll hear the first Broad-winged Bush Katydid once the Gladiators have begun.  Gladiators were a little late this year, but the Broad-winged Bush Katydids started singing right behind them.  Both sing together in the afternoon as well as in the evening.  These two species create a beautiful early-summer duet that's often embellished by bird songs when they are singing during the day. 

Finding them, however, can be quite a challenge. 

I really wanted to see some Broad-winged Bush Katydids this year, as these lovely insects  seemed much less common than usual during the previous two years.  2012 was a year of heat and drought.  Asters and goldenrods in the meadows were half their usual height.  Leaves on trees and shrubs curled and dried.  The wetlands were cracked and parched, and I was able to walk all the way across them with only hiking boots for most of the summer into early fall.  I heard almost no Broad-winged Bush Katydids.  Not surprisingly, they didn’t seem to bounce back immediately in 2013.  

But this year is better! I’m sure the copious amounts of rain we’ve received and the absolutely lush plant growth everywhere have been a big help.  Of course, all that tall, dense vegetation was not going to make my search for katydids any easier.  

 A katydid’s best defense is its camouflage, and bush katydids look amazingly leaf-life. I only saw the female below a couple of years ago because she was enjoying the afternoon sun on her leaf.

I was determined, as usual, so I tracked a Broad-winged Bush Katydid with my microphone.  These katydids have a different song in the day and in the evening, and the "day song" is rather like a short, little drum roll that crescendos to the end.   That's what I tried to follow.

The Broad-winged would do a few of these – maybe half a dozen, with any luck - and then say nothing for the next 20 minutes or so while the nearby Gladiator Meadow Katydids sang on and on. I would creep ahead as far as I could until he was silent.  Then I'd pose like a Great Blue Heron, leaning forward with an outstretched microphone instead of a bill until the next round of song.  If anyone were observing me, they probably would have called a ranger or the police.

When I was patient, he’d sing again and I’d creep closer.  When I wasn’t patient, I’d leave the spot to go look for some Gladiator Meadow Katydids and then…he’d start singing again.    

I finally made a commitment to stay in one place, and I made some progress.  It seemed that I should be able to see him.  He had to be right there!

And was he up on a viburnum or dogwood leaf?  Oh, no.  He was way down in the grasses and sedges.     

He was gorgeous, though – well worth the effort.  Here he is below as I crouched down there with him, and that’s also where I got his picture that's at the beginning of this post.

Gladiator Meadow Katydids sing the same song in both the afternoon and the evening, but Broad-winged Bush Katydids actually sing a different - and more complex – version of their song at night.  Here’s a recording of a Broad-winged singing a little of his “day song” and immediately switching to his night song (it was after dark).  

What did you notice?  It’s hard to count the number of “drum strokes” in the daytime drum roll, but you certainly can count what you hear in the night song.   (I’m going to use the drum stroke analogy because that’s how you’ll probably perceive the very fast day song. The night song sounds more like "Tchit-tchit-tchit-tchit.") 

And does the night song stay the same?  It might for a few statements, but then he adds another "tchit" and the next time, perhaps another...I've heard up to nine "tchits" before the sequence ends, though usually it's five or six.  Silence then follows until the katydid chooses to begin again.

Lang Elliott and Wil Hershberger described this as the “counting sequence” in The Songs of Insects, and that invaluable book and accompanying CD enabled me to first identify this species several years ago.  (You can now read and listen to the Broad-winged Bush Katydid species description and see Wil's sonogram in motion at Miracle of Nature’s “Our Singing Insects” - the Songs of Insects online guide.)

I've noticed that there's a relationship between the day song and the night song. Here’s how the Broad-winged’s day song appears if I make the image large enough to count:


If slowed down, it would actually resemble the night song, including the crescendo to the end.  The difference is that the number of strokes is consistent each time in the day song - it doesn't start shorter and get longer as it does in the night song.

Always interested in being out in the field at night, I attended a Moth Week celebration at the Hiram College Field Station in Portage County yesterday. While walking the trail with a group of participants, someone asked me if he’d just heard a katydid in the meadow next to the trail.

Not surprisingly, it was a Broad-winged Bush Katydid.  The tone quality is not as heavy and the song is nowhere near loud as the well-known Common True Katydid, but the percussive sound and the rhythmic pattern correctly said “katydid” to him. Our Common True Katydids haven’t started singing in the Cleveland area yet, but when they do, they’ll be up in the trees and very loud. You won’t mistake them for anyone else.  

Day or night, enjoy the beautiful Broad-winged Bush Katydids while they're here.  Their Curve-tailed Bush Katydid cousins will join them shortly, and as August progresses they will be replaced by the Texas Bush Katydids that sing until the first couple of hard frosts.

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