Grasshopper Plague at Marsin Nature Trail
The Marsin Nature Retreat is just a few miles down the road from us, and has a nice set of walking trails, so we went down there on July 5, 2021. And once there, we found that they were in the midst of the eighth plague – locusts. Here is a short video of Rosie running down the trail, and the little white objects fluttering up at her feet are the grasshoppers she was flushing up.
A lot of the ones that stayed still long enough to get a look at were two-striped grasshoppers, which have a distinctive pair of white lines running down their backs that can be seen even without catching them. I didn’t get any pictures of them this time, but here is a picture from an earlier posting:
I don’t think they were all one species, though. They seemed to vary a lot in size, with a bunch of little winged ones that were smaller than the two-striped grasshoppers and flew too fast to catch with bare hands (and we had forgotten our net). What we could catch, though, were some wingless grasshoppers, like this one that Sam snagged:
“Wingless” might actually be too strong of a term, the wings were present. They were just so reduced in size as to be absolutely useless in flight. There are grasshoppers that are completely wingless, but this isn’t one of them.
One of the issues here is that I am not absolutely positive whether this is a species that is normally short-winged. Some species of grasshoppers will have both short-winged and long-winged variants, depending on the availability of food while they are maturing. If I remember right, if there is a lot of food the female grasshoppers will divert resources from wing growth to increasing their body size, so they can lay more eggs. On the other hand, if food is short the females will grow fully functional wings so that they can migrate to a better location to lay eggs.
I think the most likely candidate is a female Dawson’s Grasshopper, Melanoplus dawsoni. They have a striped abdomen like that, and BugGuide says the wings are “nearly always short”. And the book “Orthoptera of Michigan” confirms that they have been found up here in the past.
At any rate, there were at least two species of grasshoppers involved in this little plague, and possibly many more. The conditions were just good for grasshoppers last year (so a lot of eggs got laid) and this year (allowing a lot of them to reach adulthood). They aren’t actually to the point of devastating the vegetation yet, so it is possible there will be even more next year. Unless, of course, the predators this year suddenly take notice and start scarfing them down, which might lead to a population crash of the grasshoppers next year.
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Happy birds!
Yes, at this time of year the birds are kind of spoiled for choice, there are more bugs available than they can possibly eat. Which I guess is why they migrate up here to raise their young. I gather there isn’t the same flush of “all you can eat bugs”, along with not enough predators to eat them, further south.
Are your birds sleek and plump? Here in San Diego, we have a rather scruffy lot. Without rain and good soil, their food supply is always limited.
Yes, by the end of the summer the birds around here are little butterballs. The ones that migrate burn off a lot of that when they head south, and the ones that stay here have to get through the winter and look a bit thin by spring, but overall birds eat very well up here in late summer.