Currency and Milestones

by Carl Strang

Last week, in a location just north of the Indiana border, I heard a single long-spurred meadow katydid singing in Berrien County, Michigan.

Long-spurred meadow katydid

Earlier in the season, I had found that species in two locations in Kane County, Illinois. These results amounted to two county records and a milestone in my 22-county survey of singing insects in the Chicago region. As I outlined in a blog post last year, the currency by which I measure progress is county records. The goal for each species, however, is either to find it in every county or to conclude that I have reached the limit of its range in the region. When I do so, as now is the case for long-spurred meadow katydids, it marks a milestone in the survey. I no longer need to expend time and effort in searching for that species.

The resulting map for the long-spurred meadow katydid. Black dots indicate counties where I have found the species, and red stars indicate the northernmost locations in Kane, DuPage, Cook and Berrien Counties (i.e., the range limit).

With 100 species and 22 counties, there theoretically could be as many as 2200 county records and 100 milestones. Many species are limited, however, with the edge of their range occurring within the region (as in the long-spurred meadow katydid) or else by having ecological needs which cannot be met in every county. As of this writing, I have a cumulative total of 1129 county records and 32 milestones. The year’s count is up to 87 county records. I hope to reach 100, but if I do, this will be the last year in which I can do so, as I estimate that there will be a total of only about 200 more to be found in future years. The wild card here is in the singing grasshoppers. I have not been very successful in finding these, so if I hit upon a method that opens the door to finding them, that could greatly increase the number of potential county records to be added. At this point, however, it seems more likely that most of these are very limited in their distribution.

 

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1 Comment

  1. August 29, 2017 at 5:17 pm

    Thank you for explaining this, Carl.What a helpful idea!


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