Friday, August 6, 2010

The Giant Cicadas are Back

Last year was the first year I heard chicharras grandes, Quesada gigas, the Giant Cicada. It was while taking an evening walk through Purgatory Park with my sweetie when we heard the strange sound, recorded here by one of my professors from TSU.

It starts off sounding somewhat like an ordinary insect, "chic-chic-chic-chic-chic...", but the sound keeps getting faster and faster until it blends into a loud, whistling cry. At this point, it doesn't really sound like a living creature at all, more like some sort of loud, buzzing machinery. It's been described as sounding like a locomotive whistle, a turbine engine, a toy plane, an electric drill, and a fire alarm.

Now, I'm the sort of person who actually pays attention to the nature around me, to the sounds and sights one is to expect at different times of year in Central Texas, so when I heard something completely new and so distinctive, I had to investigate.

Turns out the reason I hadn't heard them before was because they hadn't been here before!

Blue is its historic range in Texas. Most of the bug books you'd find say the giant cicada is only found in extreme south Texas, along the coast or in the Rio Grande Valley.

Red is where it suddenly showed up in 2006.

Green is where it showed up in 2009.

Or at least that's where it was reported, which means they could be in more places, but no one's told the scientists who's job is to keep track of these things. My county is one of the 2006 ones, but I didn't hear it until 2009. Maybe it was because I wasn't paying attention, maybe it was because before that I lived right by a loud freeway (that's probably the mostly likely explanation), or maybe it's just becoming more and more common and therefore easier to hear.

I heard my first giant cicada of 2010 last week, and now it's something I hear every evening around sundown if I'm outside. I guess they like the very hottest part of summer best. Makes sense for a newcomer from extreme South Texas. One hundred degrees every day must feel just right for them if they're from the Valley.

It's a cool sound, but I'm not sure how I feel about it. The giant cicada is not the only species creeping northwards from the tropics. I'm not as familiar with insects, but I do know that some birds are shifting their ranges northward, so that you can't really trust the range maps in older field guides. Great Kiskadees, Green Jays, and Northern Caracaras, according to these guides, are only found in the Rio Grande Valley and southward, but I see Caracaras all the time, Green Jays show up occasionally in the San Antonio area, and the Kiskadees are getting close. One of my professors from when I was getting my Bachelor's degree at UT was doing most of her research on the northward range shifts of butterflies.

Plants are shifting too, at least temporally, if not geographically. I've heard old timers (gardeners and farmers) remark about how fruit trees are blooming earlier each year and things like that. The point is, it's not just egghead scientists who have noticed it. Pretty much anyone who pays attention to nature's rhythms is noticing the rhythm changing.

It just seems weird to me that climate change is treated as something so... esoteric. Like only people with PhD's sorting through complicated computer models would know anything about it, and nobody who doesn't have extensive statistical knowledge would understand. No, those statistics and models only show that trees blooming earlier, tropical animals showing up farther and farther north, birds migrating at different times than they used to, sea ice forming later and melting earlier, glaciers retreating, hurricanes getting stronger, corals dying because the sea is becoming more acidic, coastlines disappearing underwater, and so on and so on, all these things happening all over the world in all sorts of different natural systems, really are all related to each other, and aren't just some amazing coincidence.

(Or at least we're as sure as we can be that they are related. One thing that frustrates people is that scientists never want to say they're 100% sure of anything. That's treated as an unattainable goal because we're working on the assumption that we can never actually know everything. But being more than 95% sure of something is generally considered to be close enough, and how sure we are about climate change is greater than that.)

Without the scientists, we'd just have people all over the planet, noticing various changes in the natural world, and going, "Huh, that's weird. It never used to be like that before," but unable to put it into a bigger picture. Each individual happening might be just a fluke, if it were just an isolated incident. After all, species shift their ranges all the time. If the giant cicadas were the only ones doing it, or if some species were going away from the equator and others towards it, that would be different. But when you start getting lots of independent things all behaving in a way that is consistent with the Earth getting warmer, that's what makes you go, "hmm, I think something big might be going on here."

(And yes, this past winter was unusually cold. Thanks to the scientists putting together all this data from all over the world, you can also see that things that seem to indicate it's getting colder are greatly outnumbered by things that seem to indicate that it's getting warmer. It's not like it's never going to freeze ever again, but one cold winter doesn't matter when having cold winters is getting increasingly rare in the long run.)

Though, what may frustrate me more about the climate change "debate" than how obvious it seems to me while others act like it's something completely unbelievable and ridiculous, is that the things people should do to fix it are things that are good to do anyway. It reminds me of a political cartoon I saw that said, "But what if we made the world a better place when we didn't have to?" Yes, how horrible it would be if we got ourselves off fossil fuels if the Earth wasn't warming after all! We'd have no more smog, no more oil spills, no more drilling in wildlife refuges, no more mercury in fish, no more coal miners dying horrible deaths in mining accidents, and no more wars over fossil fuel resources. If it turns out that climate change is either not happening, or is not due to anything humans are doing, then all that would all be a big old waste of effort, huh?

See, and I told myself when I started this blog that I wouldn't get political. It's the cicadas' fault. Every evening they make it sound like the Rio Grande Valley here. The Hill Country is hot enough already. If it turns into an ecosystem more like the Valley, then what's the Valley going to be like?

(Of course it's actually not that simple. Things aren't going to warm up evenly over the whole planet. The poles are warming much faster than the tropics. Good for cicadas. Bad for polar bears.)

Ok, I'll get off my soapbox now, but here's some links about the giant cicadas so you can see I'm not just making this all up:

Central Texas getting rare visit from ear-piercing giant cicada
Giant Cicada / Chicharra Grande
Giant Cicadas making quite a racket
Central Texas now home to the calls of giant cicadas: Our area caught in the path as loud, booming insects slowly move north.

I must admit that even though they remind me of the climate change problem (and yes, in case I haven't made it clear, I know it's not certain that this specific thing is due to climate change, it just seems consistent with the overall pattern), the cicadas are still kind of cool. I'm still a huge geek, after all. Weird things happening in nature is cool. It's just tinged with sadness, because I suspect if Texas is gaining some species, it must be losing others, which were probably just as cool. And yeah, that thing about how it's hot enough here already.

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