My brother Gary and his wife Lisa have moved from the Eastern Shore of Maryland down to coastal North Carolina, and I joined them there for the week around Christmas. Most of our time went into unpacking and some yard work, but there were plenty of moments to explore the surroundings.
One corner of their property extends into a swamp complete with bald cypress “knees.”
Some of the trees also have the iconic southern epiphyte, Spanish moss.
The most charming critter award went to the anoles that climbed the walls, shrubs and yard furniture.
It’s easy to project lots of personality into these little lizards.
Most were wearing their basic brown.
A few switched to green, demonstrating why some call them “chameleons.”
There still were several species of singing insects performing in the unseasonably warm temperatures of those days. I recognized Carolina ground crickets, southern ground crickets (song identical to that of the striped ground cricket of the North), pine tree crickets, and abundant jumping bush crickets. I was left with a mystery, two individuals of a fifth species that sang from lawns after dark. Here is a recording:
Most of the time the spacing between trills was more evenly rhythmic than in this recording.
The recording was made well out in the lawn in front of Gary’s house.
I was able to locate the presumed cricket’s position within a few square inches, but unsuccessful in seeing him. He must have been well concealed in a soil crack or tunnel. At first I thought, from the sound and the habitat, that he must be a ground cricket, but his song was louder than most ground crickets and I have never encountered a ground cricket that sings only after dark. A quick review of ground cricket recordings, and those of other likely cricket groups, in the Singing Insects of North America website, failed to turn up a match. If anyone recognizes this, I would appreciate the tip, but it was great to leave North Carolina with a mystery in hand.
The Indiana Forest Alliance is sponsoring a multi-year species survey of the back country portion of the conjoined Morgan Monroe and Yellowwood State Forests in Monroe and Brown Counties of southern Indiana. They are holding bioblitz weekends at various seasons so as to get a more complete picture than a single bioblitz would produce. Jeff and Mary Stant are providing the principal organizational and logistical support. I paid my first visit on September 12 to begin inventorying the singing insect species.
While waiting my turn to go into the survey area, I checked out the base camp in an old field with scattered young trees adjacent to the riparian edge of a wooded stream. The species mix was much like I would expect to find in a dry area in northern Indiana or Illinois.
Woodland meadow katydids were very common in woodland edges, much more abundant than I have found them farther north.
The old field held scattered common meadow katydids.
Handsome trigs also were common in the riparian edge.
Allard’s ground crickets were one of several species at the camp.
The forested survey area was, as expected, less diverse, though the cool afternoon temperature probably inhibited some species. The slopes held scattered confused ground crickets, and bottomland herbaceous thickets were full of Say’s trigs, along with good numbers of Carolina ground crickets and more scattered jumping bush crickets and narrow-winged tree crickets.
At one point we flushed out a medium-sized cricket which permitted a quick photo but evaded capture. It was one of the camel crickets, probably in genus Ceuthophilus.
We went up to a ridge top in the evening. It was very cold, and few species were managing to sing. There were scattered tinkling ground crickets, Carolina ground crickets, jumping bush crickets, and a few feebly ticking long-spurred meadow katydids. A background hum came from the forest canopy, and occasional individuals could be distinguished to support an identification of Davis’s tree crickets, by far the most abundant singers on that cold night.
I look forward to returning for more ecoblitz weekends next year.
Earlier this season I scouted some new sites in Berrien County, Michigan, and on Sunday I returned to see what singing insects I could find in the early portion of the peak season. A first quick stop at Mud Lake Bog produced a hoped-for population of sphagnum ground crickets, and I was reminded how utterly teeny tiny they are.
Most of the day, and a return trip in the evening, went into a place in the eastern part of the county called Chikaming Township Park. If this were Illinois, I wouldn’t expect much from a park district administered at the township level, but this is a good and well maintained site, and it yielded a pile of county records for my study. One of these was provided by a female curve-tailed bush katydid that flew to a landing right in front of me on one of the trails.
The dark-tipped green ovipositor with this shape and proportions, along with the katydid’s overall size and the habitat, permitted the identification.
After release, she hung around long enough to let me take a single usable, if not absolutely sharp, photo.
Perhaps the most bizarre observation came as a result of the day’s odd weather. I drove through intermittent rain to get to Berrien County, and waited out the last shower before going out onto the Mud Lake Bog boardwalk. Dark clouds remained until mid-afternoon, but they slowly drifted east and the sun was revealed at 4:00 local (eastern) time. Almost immediately, Chikaming’s swamp cicadas began to sing. These generally are limited to mornings, but here they were going in the late afternoon. This site proved to have the largest concentration I have encountered to date. At one point I wandered into a song battle taking place among a trio of males in a meadow with scattered tree saplings. One allowed a close approach.
None of our other cicadas matches the swamp cicada’s heavy black coloration.
Later in the evening I was able to pick up some additional species.
Among them was this Forbes’s tree cricket.
The highlight of the day, though, came at another site, Galien River County Park. I had set a goal for this season of listening for spotted ground crickets, which historically have been documented in several Chicago region counties, but which I had not noted to date. Described as a forest species, the spotted ground cricket’s song to my ear is similar to that of a common and widespread species, the Carolina ground cricket. I realized that while some of the forest crickets at Galien River indeed were Carolina ground crickets, others sounded a little different. I made recordings, and listened carefully, and was pleased to conclude that spotted ground crickets were there as well.
An example of a spotted ground cricket location.
The songs have a similar tonal quality and pitch range to my ear. Where the Carolina ground cricket’s song is a steady purr with intervals of added overtones, the spotted ground cricket’s song is composed of regular pulses (about 4 per second), has no overtones, and lacks the continuous steady sound.
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.
The developers who built my subdivision, in their wisdom, decided to plant mostly green ashes along the streets. That brilliance has been answered in the form of an insect, the emerald ash borer. This little invasive ash-killer has done a number on my neighborhood. A series of before-and-after shots follows, going around the block route I follow when I do my standard survey of singing insects in the warm months.
Looking north along my street in 2009.
The same block now.
Turning west in 2009.
Same view, 2013.
The next block, looking south in 2009.
The final leg, facing east in 2009.
Hard to believe it’s the same block today, but it is.
Most of the tree loss happened over a brief period of time, the second half of summer last year. Ever the opportunist, I made predictions about the response of the three singing insect species common enough for statistical comparisons between this year and last. Greater angle-wings are tree-dwelling katydids, and so I expected their counts to drop. Carolina ground crickets mainly live beneath foundation shrub plantings, so I expected no significant change. Finally, striped ground crickets prefer sun-lit lawns to shade, so I expected their numbers to increase. I was correct on two of the three predictions.
The Carolina ground cricket median count in 2013 was 7, not significantly different from 2012’s median of 5 (Mann-Whitney U-test of the ranks of all the counts led to a z statistic of 2.05, p>0.01). The median count of striped ground crickets in 2013 was 20, that in 2012 was 11. The comparison of ranks produced a statistically significant z value of 3.89 (p<0.01). I was somewhat surprised at the lack of a demonstrable difference for greater angle-wings (z = 1.00, p>0.01). The 2013 median count was 3, less than the 2012 median of 5, but the difference was not as large as one might expect. There were enough surviving trees of other species to sustain a population of the katydids, and also the removal of the nearer trees made more distant angle-wings more audible.
A continuing theme in my regional survey of singing insects is the paucity of wetland species. The only one that is present in good numbers in many wetlands is the black-legged meadow katydid. Other species common in wetlands are habitat generalists such as the Carolina ground cricket and short-winged meadow katydid, which don’t truly count as wetland insects. One clear cause of this problem is the loss of high quality habitat to four invasive plant species (purple loosestrife, reed canary grass, common reed, and cattails). All four are capable of completely taking over a wetland, and examples of this can be found for all four. Small numbers of the singing insects mentioned above can be found in such places, but not the other wetland insect species.
This female long-tailed meadow katydid was a rare wetland species holdout in a small pocket of surviving diverse wetland plants surrounded by cattails, reed canary grass and common reed at Waterfall Glen Forest Preserve in DuPage County, Illinois.
On the other hand, there are some good wetlands out there. Many are small, and this along with their isolation may limit them.
This beautiful little fen at Richard Young Forest Preserve in Kendall County is completely surrounded by woodland.
Many of the interdune swales at Miller Woods in the Indiana Dunes National Lakeshore have been taken over by the common reed. This one was an exception, but I found only black-legs there.
This fen-like wetland at Bluff Creek in Wisconsin’s Kettle Moraine State Forest looks very good. I will want to check it earlier in the season next year.
Still, I have not given up hope. I found a third good population of mole crickets this year, in a swale at Miller Woods.
Mole cricket tunnels look like miniature mole tunnels. They occur around wetland edges, and occasionally have holes to let out the males’ deep chirping calls, and to provide access for attracted females.
I also found melodious ground crickets at two new sites in Berrien County, Michigan. Though I did not find dusky-faced or delicate meadow katydids at the Indiana Dunes’ Great Marsh this year, I felt curiously encouraged by this.
Both species were there last year, but with the water level higher in 2013, the vegetation was arranged differently and I did not find them in the same place.
Maybe the populations of many wetland species took a hit in last year’s drought, and were thinly dispersed in the expanded wet areas of 2013. This is, after all, the first year in which I have surveyed many of these sites. If they need a couple years to recover from the drought, maybe I will find the missing species in the future. Still, how to account for the lack of nimble meadow katydids? This species I have yet to find, anywhere. In the heart of the singing insect season I took my sea kayak into an area where they historically were known.
The channels at the south end of Lake Maxinkuckee in Marshall County, Indiana, have become heavily invaded by purple loosestrife.
Even the patches of emergent water-dwelling knotweeds, a habitat specifically mentioned in some sources as good for nimble meadow katydids, had none as far as I could tell.
So the bottom line is a disappointing season for wetland species, with a few positive points and hope in the possibility that populations are at a low point from which they will recover.
I now have 7 years’ data in which I have noted the first and last dates on which I heard each singing insect species. This year was characterized by a mild winter followed by a warm spring and then a summer of drought. The mild winter and spring apparently were responsible for this year’s early phenology. First song dates were the earliest I have recorded in DuPage County for 17 of the 21 species for which I have 7 years of records. The chi-squared value of 77.33 (with an expected value of 3 species per cell for each rank of earliest to latest) is, of course, statistically significant.
The greater angle-wing started earlier and finished earlier this year than in any of the previous 6 years.
As for last song dates, singing insects generally finished early this year. Of the 20 species for which I have 7 years’ data, 15 had their earliest or second-earliest ending dates, and the chi-squared value was a statistically significant 22.68. This was not a particularly cold or dry late summer and autumn, so the implication is that singing insects have a fixed rate of attrition or duration of song season, so that an early start results in an early finish. The 12 species for which I have the best, most reliable records do have differences in observed song season lengths (ranges for the 7 years, and ranked lowest to highest: 18-42 days for Roesel’s katydid, 16-52 days for gladiator meadow katydid, 52-96 days for the greater angle-wing, 58-96 days for snowy tree cricket, 67-91 days for the scissor-grinder cicada, 64-94 days for the greenstriped grasshopper, 62-109 days for Linne’s cicada, 72-105 days for the dog day cicada, 81-107 days for the common true katydid, 107-139 days for Allard’s ground cricket, 111-141 days for striped ground cricket, and 113-143 days for Carolina ground cricket).
The number of clear, cold nights seemed high enough in November that they might partly explain the early conclusion of common ground cricket songs this year, especially given the recent study by MacMillan et al. (2012) indicating that there is a metabolic cost to recovering from cold-temperature paralysis. However, I found no significant relationship between last song dates and the number of November days with low temperatures below 33F over 2006-2012 for any of the three species (Spearman’s r values 0.51 for Allard’s ground cricket, -0.39 for striped ground cricket, and 0.33 for Carolina ground cricket). It is interesting, though, that I have seen a few red-legged grasshoppers active a couple weeks after the last ground cricket.
An early December red-legged grasshopper
This bigger insect may have larger fat reserves to draw upon and so extend its season.
Ground crickets are the most difficult group of singing insects to photograph. I have spent hours seeking the various species, and still do not have photos of both genders of several species for the guide I have been developing for the Chicago area. Females are easier to find. For one thing, they wander more.
Females come out into the open sometimes as they travel in search of singing males or oviposition sites.
The acrobatic individual in the above photo is a Carolina ground cricket. I also held one in a jar briefly, but when I released her she escaped before I could get a sharp photo.
Of our common three ground cricket species, the Carolina female is distinguished by her short ovipositor, shorter than the femur length.
Of course, to some degree if you have seen one ground cricket you have seen them all. Here is a female striped ground cricket.
The longer ovipositor, subtle differences in body proportions, and especially the stripes on the head separate this one from the Carolina ground cricket.
The third common species is Allard’s ground cricket. Here is an earlier photo of a female.
There is head striping here as well, but sometimes it is obscure.
Fortunately for monitoring purposes, the male songs of these three species are easily distinguished. And after all, since they are going mainly by the songs themselves, there is little if any selective pressure for them to look different. Still, I want those photos. I still need one of a male Carolina, and that is my final field research goal for this season.
One of the obstacles to a singing insect monitoring program is the large number of various songs that need to be learned for identification. This is not really much different from learning bird songs for breeding bird monitoring, however (except that the total number of species is smaller here). Instead of being daunted by the entire process, it is possible to take the learning process in stages, beginning with the songs that are common and easy to recognize, the ones you have been hearing all along but simply didn’t have the species labels. Here is a list of a dozen suggested species to start with in the first stage: spring field cricket/fall field cricket (their songs are identical), Allard’s and striped ground crickets, snowy tree cricket, common true katydid, black-legged meadow katydid, greater angle-wing, round-tipped conehead, dog day cicada, scissor-grinder cicada, and Linne’s cicada (for more information on these species, try the tags at the head of this post).
Snowy tree cricket, one of the species on the starter list
This list and those that will follow are for northeastern Illinois and northwestern Indiana. There would be substitutions in other parts of the country (I encourage readers elsewhere to make comments here with their own suggestions). Go to reference recordings of these species’ songs, either on-line at the Singing Insects of North America website or through the CD that accompanies the Songs of Insects book. It is not too late this year to hear many of the species on this list on the warmer days, though some are finished or nearly so.
My recommended species list to focus on in the second stage of learning consists of 8 species and groups of species: greenstriped grasshopper, gladiator meadow katydid, Roesel’s katydid ( three species that sing relatively early in the season), and then later, Carolina ground cricket, Say’s trig, sword-bearing conehead, two-spotted/narrow-winged tree crickets (no need to worry yet about separating the two), and the meadow tree cricket group (3-4 species whose songs are essentially identical to the ear and will remain so).
Roesel’s katydid is a species from the second-stage list.
This list of common species either will take you to additional, though still readily available, habitats, or else require a little more of a practiced ear (which practice you got with the first species group). In particular, seek out and spend some time getting familiar with the songs of the Carolina ground cricket and Say’s trig. They need a little more effort to recognize in the field, but once you have them, they will be touchstones for many other species (much as robin songs are for learning bird vocalizations). If you are starting now, you might push the Carolina ground cricket to the first list, as it is one of the few species singing on the cooler days and evenings.
Once you have mastered the second list of species, you are ready for the more subtle distinctions needed to distinguish the songs in the third species list. This includes separating out the song of Linne’s cicada from similar songs by the lyric cicada, and in some areas, swamp and/or northern dusk-singing cicada.
Also, by this point you are ready to distinguish the two-spotted tree cricket song from that of the narrow-winged tree cricket. Also, the broad-winged tree cricket should stand out now from other long-trilling species. In addition, you no doubt have noticed and begun to puzzle out other species that are more idiosyncratic in their distribution or smaller in numbers that you have encountered in your favorite places.
And that brings you to the fourth stage, learning the songs of whatever remaining species may live in the area you wish to monitor. For this you will need a regional guide. In the Chicago region, you can meet this need with the guide I am developing. It is available for free as a .pdf e-mail attachment. Simply request it at my work e-mail address: firstname.lastname@example.org
As you are learning and listening, pay attention to which songs you can hear clearly, and at what distances, and which are marginal. This will inform the limitations you will need to address or acknowledge in your monitoring.