As I listen for singing insects in the summer, at this point I recognize nearly all that I am hearing. Sometimes I hear something that obviously is new and different, as was the case with the green-winged cicada last summer, and I put in the effort needed for an identification. Sometimes a sound is so rarely heard that I am inclined to pass it off as an anomalous sound from a familiar species, though I store it in memory in case it turns up again. Today’s story is a case in point. On a couple occasions last summer I heard songs with the pattern of a confused ground cricket, brief trills with brief spaces between them, in a fairly regular rhythm. The problem with this was that the singers, which I was unable to see, seemed to be above the ground, and they were in wetland edges rather than upland woods. The sound quality was similar to that of Say’s trig, and I figured that this might be an alternate song of that species.
Say’s trig is a common small cricket.
The typical song of this species has been well described as a “silvery trill.” Here’s a recording:
As I dug through my past recordings, I was surprised to find that the one I had made of a temporary captive in my house had the interrupted pattern:
There was no question of the singer’s identity. I also found a field recording of this pattern, at Fullersburg Woods near Salt Creek:
In this example the rhythm is less regular, and leads in the end to an extended normal trill. I am not finding a reference to this interrupted version of the song in the literature I have. It could be a context-driven alternative, or possibly individual variation. I’m certainly not prepared to suggest a different species, though new species in this genus continue to be sorted out.
There are 3 species of ground crickets that occur throughout the Chicago region (I still lack 2 county records for one of these, but expect to make up that deficit on a future Wisconsin trip). The ground crickets are the LBJ’s of singing insects (birding jargon: “little brown jobs” refers to sparrows, wrens and the like which are quick to vanish before they can be identified). Most ground crickets look identical at first glance, are tiny, and usually are brown. I’ll begin with the striped ground cricket.
The stripes are clear on this female striped ground cricket’s head.
This is the weediest of the ground crickets, first to show up in disturbed sites, and abundant in lawns. Its song consists of separate brief rough buzzes, continuously produced at 2 to 3 per second. It is low enough in pitch to hear easily, with most of the buzz’s sound range below 7 kHz. Here is a recording (complete with background bird songs and the usual traffic rumble):
The second species also occurs in open areas, but mainly where the grass is taller and vegetation better established.
Allard’s ground cricket is a close relative of the striped. The head stripes are absent, faint, or incomplete, however.
The song consists of incessant, separate quick very high-pitched notes (6 kHz) that sound like 4-6 per second but sonographs show twice that rate. There are fairly frequent, very brief pauses (again, birds and this time a train in the background):
Now I will toss in a fourth species. The tinkling ground cricket is less widely distributed than the others (so far I have found it in half of the region’s counties), but include it here to provide a comparison to the Allard’s song. Here is a recording:
The song consists of high pitched (7 kHz) individual notes, like those of Allard’s ground cricket but distinctly slower at a given temperature (1/3 to ½ as rapidly produced). It often is rendered “tink-tink-tink…” The song is uninterrupted, lacking the frequent breaks characteristic of Allard’s ground cricket (this is especially helpful late in the season, when Allard’s often slows down). The tinkling ground cricket lives in open woodlands and woods edges, and is especially abundant on sandy soils. It looks different, too.
Tinkling ground crickets have reddish tones that distinguish them from our other ground crickets.
The final, common species is the Carolina ground cricket.
The Carolina ground cricket has faint head stripes. The female is distinguished by an unusually short ovipositor.
Its song is a continuous, irregularly pulsed drone, purr or trill with periods when additional pitches are added to the song, making it more dissonant. Though the sound pulses are broad enough in pitch range to qualify as a drone, it is not far from a trill, and low enough in pitch to be heard by most, at 6 kHz. Here is a recording:
As the passing geese perhaps imply, Carolina ground crickets prefer moist habitats, from wetland edges to bottomland forests. In my residential neighborhood they are fairly common, but stick to the cooler, moister foundation shrub plantings against the houses.
We’ll have to wait a while to hear these crickets again. They winter in the egg form, and need until the very end of June or, more often, July to develop to the point where they begin singing.
When I mention the coneheads to people unfamiliar with singing insects, the response almost always is a smile. I have to agree: one reason why the slightly musical conehead is my favorite singing insect (at the moment) is that name. Our coneheads are all katydids in genus Neoconocephalus. I have been fortunate to spend some time in the field with Gideon Ney, a Ph.D. student at the University of Missouri who is working out of a lab led by Johannes Schul that has done a lot of work with the evolution of that group. Thanks to Gideon I am aware of two species of coneheads that are not supposed to occur as far north as the Chicago region, but turn out to be at least locally common. Today I share recordings of the 6 documented species in the region. Warning: these are not delightfully musical or even (despite the name mentioned above) slightly so. We’ll ease into it with one that is somewhat pleasant to hear: the sword-bearing conehead. Its song:
That recording was made in a grassy upland meadow, typical habitat for the species, but close enough to the edge of the woods that a few common true katydids came through loud and clear. The conehead’s song is the continuous string of rasping ticks or brief buzzes. It has been compared to the sound of a sewing machine or a distant steam locomotive.
The sword-bearing conehead is named for the very long, straight ovipositor on the female.
The next species also has a discontinuous song. The slightly musical conehead was given that name because W.T. Davis, who described it, thought it was not very loud (though he later changed his mind on that point).
The rasping sounds are easy for me to hear even with my older ears. This is a wetland species, and the males typically sing in unison.
The coneheads are named for the structure on the tip of the head, especially prominent in the slightly musical conehead.
Another species with an interrupted song is the Nebraska conehead.
The buzzes are not as rough as in the previous species, and will be heard in bushy undergrowth of woodlands, or sometimes bushes out in fields. In the southern part of the Chicago region, where the species is more common, the males sometimes sing in unison as well.
Male coneheads often sing head down. It has been speculated that the cone helps them penetrate the vegetation beneath when they are disturbed and drop to hide. Nebraska coneheads have medium sized, all black cone undersides.
The remaining 3 species all have continuous buzzes. Most common region-wide is the round-tipped conehead, a katydid of meadows and roadsides.
Listen for a crackling sound in this continuous buzz.
Here the cone is short, round, and has a small black area near the tip.
Next is the marsh conehead, which so far has turned up only in the marshes of the Indiana Dunes parks.
The sound resembles that of the round-tipped, but comes from a wetland rather than dry upland habitat.
The cone of the marsh conehead may be all green as in this female, or show variable darkness of color.
For the grand finale, here is the very loud song of the robust conehead:
This can be so loud as to be painful to the ears. It carries for long distances, as you may imagine, and is easy to hear from a car at any speed.
The robust conehead’s cone is unmarked and proportionately short. Any conehead species can come in green or brown.
The robust conehead is most abundant in areas with dry sandy soils. Its habitat range is fairly broad, from open woodlands to prairies to corn fields.
There are at least two other species which are supposed to occur in the region, but which I have not found. Perhaps next winter I will have recordings of false robust coneheads and slender coneheads to share.
Today I wish to share recordings of 4 species of our tree crickets, which have in common songs that are continuous (rather than interrupted) trills. I will order them along a typical habitat gradient, from grasses to mixed grasses and forbs to mixed forbs and shrubs to trees (specifically, conifers).
The four-spotted tree cricket seems to prefer to sing from grass stems.
Four-spotted tree crickets are pale.
The song is a continuous clear trill:
Very abundant late in the season, Forbes’s tree cricket prefers forbs or vines.
Forbes’s tree cricket is highly variable, but usually has some dark markings.
Here is a recording from last year:
There is an interesting issue surrounding these first two songs, in my mind. I know of other singing insect students who, like me, at least sometimes can distinguish the songs of four-spotted and Forbes’s tree crickets, but we describe them with different language. To me, the four-spotted’s song has more of a clear, tone-like quality, while the Forbes’s song has a discordant tone that others apparently don’t hear. Others point to the difference in pulse rate (much faster in Forbes’s, but I need a computer analysis of a recording to tell that difference). This is the best example I have found of how describing insect songs in words can be difficult, and may in some cases be impossible.
Woodland shrubby understories to masses of forbs in open places near wooded edges are habitat for our third species, the broad-winged tree cricket. Here is its song:
Broad-winged tree crickets are distinguished by the wide wings and the raspberry coloration on the head and antenna bases.
To my ear, this song has a richer tone, and usually is lower in pitch than other trilling tree crickets at the same temperature.
I’ll close with the pine tree cricket, perhaps the most beautiful of the four.
The red-browns and pale greens provide good camouflage in a habitat of coniferous trees.
The following recording was made indoors, from a caged male (you can hear the splashing of the aquarium pump in the background):
Again the trill is continuous and similar to the others, especially the four-spotted tree cricket, but the source of the sound in a pine, spruce or cedar (usually in a grove of them) is a dead give-away.
Today’s chapter in the Sound Ideas winter series is a recording from the evening of September 4 last year. I made it in the Miller Woods portion of the Indiana Dunes National Lakeshore. Three very different singing insects can be heard distinctly throughout:
The principal target of this recording produced the annoying, continuous buzzing sound. If you had been there, you would have remarked at how loud this insect was. It was a robust conehead.
Male robust conehead, singing posture
This katydid has a sibling species, creatively named the false robust conehead (Neoconocephalus bivocatus). I haven’t documented bivocatus in the Chicago region, but there are a couple old possible records, so occasionally I record an individual and check the pulse rate and pattern. So far, all have been good old Neoconocephalus robustus.
The other two members of that night’s trio both produced regular, brief chirps: one higher pitched and very regular in its rhythm, the other much lower and a little less regular. The higher pitched singer is famous for the way its chirping rate varies with temperature: count the chirps in 13 seconds, and add 40 to get the degrees Fahrenheit. We know this singer as the snowy tree cricket.
Snowy tree cricket male, taking a break from singing to snack on skin.
That leaves the bass section. The lower pitched continuo is the product of a northern mole cricket. This swale area of Miller Woods is one of only 3 locations where I have found this species to date. I don’t have a photo to show you. True to his name, the mole cricket sings from within his tunnel, and I haven’t yet had a photo op with the critter.
Ah, yes. I see an insistent hand upraised in the back of the class. Yes? Ah, very good. Yes, there is a fourth, more intermittent performer here. Those few added chirps are a fall field cricket’s, practically ubiquitous at this point in the season, and determined to insert himself into any ensemble.
Singing Insects of the Chicago Region, the guide that summarizes my survey work on this subject, now is available in its newly updated version.
This edition is pushing 90 pages, with several added species pages, an expanded section on hypotheticals (mainly grasshoppers), over 300 new county records for the covered 22 counties in Wisconsin, Illinois, Indiana and Michigan, and an expanded introductory section with topics such as conservation concerns, dispersal ability, and range extension.
This guide is available for free as a 3-meg PDF document. If you are on the mailing list you already should have received it. If you wish to be added to the mailing list (which is used for no other purpose than to forward annual updates of the guide), send a request to my work e-mail address: firstname.lastname@example.org
In the vegetation that grows just behind the beaches around the western Great Lakes you may hear a very rapid, high-pitched trilling sound, as in this recording I made at Whitefish Point (on the north side of the tip of Michigan’s Upper Peninsula) on September 16, 2009:
The area where the previous recording was made.
This interrupted trill is identical to the reference recording for the gray ground cricket on the Singing Insects of North America website. Indeed, this species is expected in open, sandy soil habitats. The only other ground cricket song I have heard that is close to this is that of the sphagnum ground cricket, which is restricted to sphagnum bogs and could not survive on sand. Allard’s ground cricket, when it occurs with the gray ground cricket, has a distinctly slower song.
The challenge for me with this species has been two-fold. First, I have never seen one. Second, I am pretty sure they occur inland as well. Here is a recording from Braidwood Dunes, a Will County Forest Preserve, September 7, 2011:
At the time I noted that there were pauses, but enough crickets were singing simultaneously that these are difficult to pick out in the recording. I have heard, and sometimes recorded, this same song in other inland locations in Kendall, Marshall and Fulton Counties. Sometimes the pauses are infrequent or nearly absent, but the songs all have a peak frequency of 8-8.5 kHz, and share similar patterns of amplitude irregularity in their sonographs. I am not aware of any other cricket that could occur in dry soils with a song like this. Furthermore, there are some mentions of inland gray ground crickets in the literature, and some authors refer to the trill as continuous. So, mainly by process of elimination I have decided to refer to all these crickets as gray ground crickets for now, but with a higher priority of catching one, particularly at one of the inland sites, for confirmation.
I have made a correction to yesterday’s post on green-winged cicadas. I always check my posts when I get to work, to make sure nothing is lost in the translation to another computer. In the process of checking links, I went to the Cassin’s 17-year cicada portion of the Michigan cicada website. There I saw something I hadn’t noticed before, mention of “Court II” and “Court III” signals. The Court III signal is produced by a male cicada as he connects with a female for mating.
Cassin’s 17-year cicadas, mating pair
When I played the Court III signal recording, it proved to be what I had attributed to green-winged cicadas in 2007. That both corrected my impression of Diceroprocta in DuPage County, and removed any confusion about my observations in 2013.
One of the singing insects I have been seeking for several years in the Chicago area is the green-winged cicada (Diceroprocta vitripennis). Some references have suggested that this is an early-season species, and I thought I heard them in June of 2007 (the brief regular buzzes in the following recording, with Cassin’s 17-year cicadas in the background):
Those sounds were very similar to the cooler-temperature recording of Diceroprocta at the University of Michigan’s cicada website, though a little slower (the temperature was about 10 degrees cooler). The problem was that the periodical cicadas were in their peak year and season at the same time, and the identification was ambiguous because I couldn’t entirely rule out the possibility that these were Cassin’s 17-year cicadas warming up. Returns in subsequent years to places where I heard those sounds failed to turn up a repeat performance. Now I find that those actually were “Court III” signals of the Cassin’s cicadas, produced by the male as he connects with a female for mating.
During my survey work this past field season, I finally heard green-winged cicada songs on July 29, first at Willow Slough Fish and Wildlife Area, then at Jasper-Pulaski, both in Indiana (a scissor-grinder cicada song is in the background at the start):
Oak woodlands on sandy soils, including this one at Jasper-Pulaski Fish and Wildlife Area, are where I heard this song.
These were a match for the warmer-temperature song at the University of Michigan website (the temperature was cooler for my recording, but the insect may have had a warm perch in the sun; I didn’t see it). That day was the extent of my experience with this species, though, so more observations are needed to get a better handle on the abundance, distribution and habitat of green-winged cicadas in the Chicago region.
Back in early July I first encountered a species I then called the short-grass prairie cicada (Okanagana balli). Its more commonly used English name has proven to be simply “prairie cicada.”
Prairie cicada. These are little guys, about an inch long.
Here is one of the recordings of its song that I made at Woodworth Prairie:
The song doesn’t change, so you may decide not to hear all of the recording, though if you listen carefully toward the beginning you may hear a more distant individual when the recording’s main subject pauses. The song was loud enough that someone with younger ears, or me with the SongFinder pitch-reducing device, could hear it from more than 100 feet away. Unaided I needed to be within 20 feet or so.
The song is continuous, and simple, but there are so few other insects singing in late June or early July in the prairies that there is no confusion. Females clearly have no problem homing in on the singing males.
Prairie cicadas preparing to mate.
I have made a list of places in several counties where I will be seeking this species next year. I want to test the hypothesis that this is a species of prairie remnants and not of restored prairies.