Canadian and Say’s Cicadas

2010 July 10

I used to think that (a) there was only one kind of cicada native to this area, and (b) I would know a cicada song when I heard it. It turns out I was sorely mistaken on both points.

For the last couple of weeks, we’d been hearing an obviously insect-produced sound around the yard that we hear pretty much every year and that I’d always thought was made by some kind of cricket. It sounded like this[1]:

Link to Canadian Cicada song

But then, S_ found our copy of the CD that accompanies The Songs of Insects, went through all the tracks looking for a match, and realized that what we were actually hearing was Canadian Cicadas, Okanagana canadensis. So, Sam and I decided to go out and try our hand at cicada hunting. I’d never had much success doing it before, so we thought it was a long shot, but what the heck, right? Anyway, the method we hit on was to locate a tree that had a cicada calling in it, then position ourselves about 90 degrees apart around the tree and both point at the spot we thought it was coming from. Then we both advanced on the tree, still pointing, until it got alarmed and stopped calling. We then checked out the spot we were pointing at until we found it. Although, it turned out that the call we were tracking was a bit different than the one for the Canadian Cicada, it sounded more like this:

Link to Say’s Cicada song

and the insect we tracked down and netted from a poplar tree looked like this:

Say's Cicada

This is, it turns out, Say’s Cicada, Okanagana rimosa[2]. Heartened by our unexpected success, S_ then went out to try and catch one of the Canadian Cicadas by herself. Her method was to slowly spiral in around the tree to get a good idea of the location, and then search the spot. She was also successful, and caught this in a small pine tree:

Canadian Cicada

These are obviously very closely related. The distinguishing features are:
(1) Obviously, their songs (Canadian cicadas have a fast trill [3], while Say’s cicadas have a more continuous buzz that sounds kind of like an AC electric arc); and
(2) Their coloration – Canadian cicadas are black with yellow markings

Canadian Cicada

while Say’s cicadas are black with orange markings

Say's Cicada

Like other cicadas, the life cycle is that the nymphs live underground sucking on tree roots for an extended period of time (in the case of these two species, the time is evidently 4 years). They then dig out of the ground in the summer and emerge as adults, who live for about a month while subsisting on plant juices that they suck up with their piercing/sucking proboscis. The males call from high places, while the silent females seek them out to mate. The females then lay their eggs in slots that they cut in tree branches. When the eggs hatch, they fall to the ground and burrow in looking for roots to suck on, and then it’s eat and grow until they are big enough to emerge.

Canadian Cicada Face

Say's Cicada Face

Given the close similarity between them, I would not be at all surprised to find that they could be interbred. Probably the only thing that keeps them distinct species is that the females are attracted only to the song of their corresponding males, so they don’t get the opportunity to cross-breed.

So anyway, now we know what it is that makes a lot of the summer insect songs in this area. It really does change one’s awareness of sounds when you know what is making them. I’d been vaguely aware of these songs before, but now that I know that they are cicadas, I am noticing them everywhere.

Now we just need to go through the rest of the CD. According to the range maps in The Songs of Insects,, there are about 22 species of singing insects that could plausibly be in this area, and for 17 of them we are solidly within their reported range. At the moment, I think I can identify 6 of them by ear[4]. Only 11 or so more to go!

[1] The two recordings were actually the best of several attempts, using the old Canon A95 camera in video mode, and held only about three feet away from the cidada singing. Then I downloaded the video clips to the computer, and used Virtualdub to extract the audio track by saving as a .wav file. The fidelity of the recordings isn’t perfect, probably because the A95 is showing its age and is developing a lot of mechanical quirks – it probably isn’t going to survive much longer. Both recordings sound to me like they are a bit lower-pitched than they were in real life.

[2] This is a little odd: this is evidently one of the approximately 1400 species that Thomas Say[5] discovered and named[6], but I’m not sure when he would have done that: he spent most of his career down in Indiana, and the range maps for this cicada don’t show it living anywhere near that far south. Either its range has contracted considerably since the 1830s, or Say discovered it during one of the expeditions he was part of, maybe the one that explored the tributaries of the Missouri River.

[3] There is a yet-to-be-identified bird(?) around that sounds superficially like the Canadian Cicada, except that the chirps have a slightly cleaner tone, and it can only keep it up for a few seconds, probably because it has to stop and breathe. Cicadas don’t have the stop-to-breathe problem, because their sound-generation system has nothing to do with their respiratory system, so they can keep it up for a minute or so. Still, I kind of wonder whether the bird can mimic the cicada well enough that it can lure female cicadas in to their doom.

[4] That’s the Spring and Fall field crickets (which actually sound the same, but at different times of year); the Carolina Grasshopper (which crepitates); and three species of cicada (these two, and the Dog Day Cicada which sounds a lot like a circular saw cutting sheet metal)

[5] Naming can get a bit confusing. Some of the animals that are referred to as “Say’s {insert kind of animal here}” were actually discovered by him, while others were named after him by others (and Say may never have even seen them). You can tell them apart by looking at the latin species name – if the species is something like “sayi”, “saya”, or “sayana”, then somebody else named it after him, while if the latin name has nothing in it that looks like “Say”, then it is one that he discovered.

[6] To paraphrase Tom Lehrer: It is a sobering thought to realize that, when Thomas Say was my age, he had already been dead for a year.

5 Responses
  1. July 10, 2010

    I wouldn’t have recognized either of those as Cicadas. They sound so different from the Texas versions that are driving me crazy this very minute.

  2. July 10, 2010

    Joy K: No kidding. They don’t sound *anything* like the Dog Day Cicadas.

    KT: Actually no, you completely blindsided me with that one. Although, now that you mention it – Barry White? Male Cicadas? Obviously brothers.

  3. kaysa permalink
    July 11, 2010

    I have a perfectly functional A95 you can have if you want. I bought a new camera, and am unsure what to do with the old one.

  4. Della3 permalink
    August 31, 2010

    Do you get mockingbirds in your area? They can immitate many things. Then again, they usually alternate between different sounds on their own customized time-schedule. But if they were deliberately hunting a certain insect, perhaps they would stick to a certain call. It would be interesting if you ever discovered who the shrewd bird was.

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