Braidwood Dunes etc.

by Carl Strang

Last week I traveled to southern Will County to seek singing insects in sand country. My main stop was the Braidwood Dunes Natural Area, managed by the Forest Preserve District of Will County. I only got into part of it, and what I saw was outstanding.

There was an extensive dry prairie on sand soil dominated by little bluestem, for instance.

That prairie hosted the largest concentration of common meadow katydids I have encountered to date. In DuPage County I have found only scattered individuals and tiny groups.

It was a windy day, and the katydids were very shy. I took maybe 20 photos to get a couple that were only slightly blurry.

One of the species I specifically was seeking was the gray ground cricket. In places that were very similar in vegetation and soil to those where I heard this species at Illinois Beach State Park, I heard trills that sounded the same in memory.

One of the places where I heard probable gray ground crickets.

I made a recording, and cannot distinguish the sound, in trill speed or tonal quality or pitch, from that in a recording I made at Whitefish Dunes in the U.P. of Michigan a couple years ago (where the only candidate is gray ground cricket). Having no permit, I was not about to try and capture, let alone collect, specimens, so comparisons of recordings will have to do for now.

Otherwise, I heard mainly common species at Braidwood Dunes. I was happy to discover long-spurred meadow katydids in a wooded area, and I also made an observation that at first seemed trivial but later proved more substantive. It seemed that the Allard’s ground crickets were slowing their trill by a huge amount in shaded areas under trees. By the time I made the day’s final stop at Forsythe Woods Forest Preserve, I had realized that the slow ones might have been tinkling ground crickets, a sibling species of Allard’s. I made a recording of one there, and it proved identical in tonal quality and pitch, and in fact had a slightly longer spacing between notes, than the confirmed recording of a tinkling ground cricket by Lang Elliott and Wil Hershberger. This experience highlighted the emphasis here and there in the literature that the tinkling ground cricket is a species mainly of dry woodland edges.

My other stops were along the Kankakee River in my continuing search for variegated ground crickets.

I stopped first at a place with a long sandy river edge.

No ground crickets in the sand.

I also found a stretch with a significant pebbly shore.

The only ground cricket here was a single Carolina ground cricket. That’s it for seeking variegateds this year. Next year I may try for them in areas where they apparently are more concentrated, in southern Indiana. Once I have experience with the species, I may have a better idea of where to look in northeast Illinois.

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3 Comments

  1. sam droege said,

    September 13, 2011 at 6:28 am

    Carl

    As always, I look forward to your posts. I have been using the music editing freeware called Audacity recently and wondered if you ever process any of your recordings through such things to get the spectragrams…I imagine that you do, but haven’t seen you post any (perhaps my oversight of earlier posts?).

    Keep up the good work.

    sam

    • natureinquiries said,

      September 14, 2011 at 5:38 am

      Hi, Sam,
      That is one dimension I haven’t gone into. It’s a good thought, for possibly sorting out similar songs. I don’t know much about spectragrams, but if they provide a ready measure of pitch, pulse rate, etc., that would be a big help. One concern is all the background noise one gets in field recordings that might fuzz up the graph. I’ll check out that program as a winter project. Thanks!
      Regards,
      Carl

  2. August 27, 2012 at 6:13 am

    […] County, a group organized the Nina Baki of that county’s Forest Preserve District. We started at Braidwood Dunes, finding the same species that I encountered in my first visit there a year ago, plus a few more. […]


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