Monday, March 19, 2018

Cricket Songs: General Characteristics of Pitch and Rhythm

Having looked - and listened – to how crickets and katydids sing, the next step is to explore the nature of their songs. We’ll get more specific later, but I think it’s essential to know the general characteristics first. I’m going to focus on two basic musical elements: pitch and rhythm

Let’s start with the crickets. We can often hear crickets more clearly and more easily because their songs are actually much lower in pitch than most of the katydids. (We’ll explore katydid songs in the next post.)


Insect song is not like birdsong. Unlike most songbirds, crickets do not change pitch during the course of a song. They do not create little melodies. (Slowing down their pitches will not create “God’s Cricket Chorus,” no matter what you may have encountered on Facebook.)

Here’s an example:

Notice that the Tufted Titmouse song has two different pitches. It’s a simple song that we could imitate – just in a lower octave than the Titmouse because we humans can’t sing that high. 

One pitch is higher than the other, and the two notes alternate in a simple higher-lower pattern. The rhythm of this short song is repetitious, and then there’s a short pause. After this brief rest, the Titmouse sings the song again (and again and again). 

The Snowy Tree Cricket has a pitch that we could also imitate as long as we sing it in a lower octave.  But notice that I said “a pitch.” Just one. The cricket can’t change pitches in the course of his song like the Titmouse. He can repeat his single note at a very steady rhythm, but it’s just one pitch.

You can see the higher-lower alternation of the Titmouse song in the sonogram, and you’ll also see that the Snowy Tree cricket’s song is a repetition of the same note at a steady rhythmic pace.

As with birds, different species sing at higher or lower pitches from each other. Before we take a look and listen to the wide range covered by all NE Ohio's cricket species as a group, let's start with a quick terminology clarification. 

I’ll be referring to “frequency,” which is a specific indication of how high or low a pitch is, not how often it occurs. The term “hertz” is used as a measure of frequency. 3000 hertz means 3000 cycles per second and is abbreviated as 3000 Hz or 3 kHz – kilohertz. 

I’ll make this more accessible by providing birdsong, human voice, and even piano comparisons to provide a concrete context. For example, middle C on the piano is 261.6 Hz. My general singing voice range is between about 220 and 880 Hz. We’re going to be listening to singers whose performances are far higher than those of humans!

Tree cricket songs resemble the pitch range and clarity of birdsong, which is why I paired the Tufted Titmouse with the Snowy Tree Cricket in my earlier example. These crickets sing between about 2500 and 4000 Hz, and common birds such as the Black-capped Chickadee, Tufted Titmouse, Eastern Bluebird, and Baltimore Oriole sing in the same range. The lower of the two notes in the Titmouse song recording was almost identical to the Snowy Tree Cricket's single pitch: about 3000 Hz. 

I’ve recorded Field Sparrows whose songs ascend from about 3500 Hz up to a little above 4000 Hz. Listen to an example of a Four-spotted Tree Cricket singing at about 4000 Hz followed by a Field Sparrow’s song in the same range:


We’re going to listen to smaller crickets with higher songs next. All of them sing above the highest note on the piano, which is only 4186 Hz.

The tiny trigs - just ¼-1/3 inch in size - sound about an octave higher than the tree crickets, ranging between 6000 Hz for the Spring Trig up to around 7000 Hz and above for the Say’s and Handsome Trigs (pictured below.)

Handsome Trig singing

Although quite high, these songs still sound like musical notes. Bird songs in similar ranges include the Grasshopper Sparrow, Henslow’s Sparrow, and Cedar Waxwings (pictured).

Ground crickets also sing much higher than tree crickets. Their songs are between 6000 and 7500 Hz. In addition to being very high, many of them sound less musical because the tone quality is buzzier to our ears. The most musical among them – at least in our region – is the Allard’s Ground Cricket with his rapid, sparkling song. The Striped Ground Cricket has a more buzzy sound and a steady, rhythmic "zit-zit-zit" song. This is an Allard's (pictured) and a Striped singing together. 

Finally, here’s a representative example of the entire range of cricket song in NE Ohio: an example that strings together a Mole Cricket, Narrow-winged Tree Cricket, Black-horned Tree Cricket, Spring Trig, Allard’s Ground Cricket, and Say’s Trig.

Rhythm and phrasing

It’s all about rhythm and phrasing with insect songs. Many cricket species have rhythmic patterns we can learn to recognize. Others have long songs that are a continuous stream of very fast notes called a “trill.” 

The Fall Field Cricket and the Jumping Bush Cricket both sing a long series of chirps that may even occur at the same pitch, depending on temperature. What’s the difference? The Fall Field Cricket’s songs will be much faster and have less space between them than those of the Jumping Bush Cricket. (Both are singing at around 5000 Hz in this particular track. Photo: Fall Field Crickets.)

Here’s a Snowy Tree Cricket followed by a Narrow-winged Tree Cricket (photo below). Their distinctly different rhythmic patterns help us identify them in the field, which is helpful because they may be in the same habitat or even in the same tree or shrub.

The Broad-winged Tree Cricket sings a long, very fast, continuous trill without rhythmic pauses; the pitch, as you would expect by now, stays the same throughout. Black-horned and Forbes’s Tree crickets (which look and sound identical) also sing continuous trills, as do Pine Tree Crickets and Four-spotted tree Crickets. This group is a challenge because they do not have rhythmic patterns that help us identify them when we can’t see them, and we’ll address that challenge in greater detail when we explore groups of similar species. 

Finally, listen to these three common ground crickets: the Carolina Ground Cricket, the Allard's Ground Cricket, and the Striped Ground Cricket. They look so similar that it takes a great deal of practice to tell them apart. However, the rhythm of their songs makes the different species quite obvious!

Temperature changes everyone’s pitch and tempo!

Finally, the pitch of all these crickets will be higher in warm temperatures and lower in cool temperatures. Keep in mind that they are cold-blooded individuals. They move much more quickly when it’s quite warm. They can run and jump faster, and they can also move their wings faster and sing higher. 

It’s important to remember that temperature affects all of the crickets and katydids.  The entire insect orchestra will sing faster and higher when warm. As temperatures drop at night, the entire ensemble sings slower and at a lower pitch.

This is the reason we cannot identify crickets by their pitches. The pitch you will hear in a field guide recording is only true at the same temperature as when the recording was made. Here are some examples:

The first is a Snowy Tree Cricket singing at 84F, then 66F, and finally at 61F.


Did you notice that the second and third series of songs were  both slower in tempo and lower in pitch? For this species, you can even calculate the temperature by counting the number of chirps in 13 seconds and then adding 40. 

If the temperature is not identical on two adjacent plants or a different part of the same shrub, that small difference will be revealed by the songs of two nearby individuals. In this recording, you’ll hear two nearby Snowy Tree Crickets in the same flowering raspberry singing almost – but not quite – the same pitches. They are not completely in sync rhythmically, either, because the one that’s a bit warmer is singing just a little faster. Yes, they are that sensitive to temperature! You'll hear each one separately, then both together. 

Now listen to the difference in pitch between a Broad-winged Tree Cricket on a warm evening and another at 58 degrees. The frequency drops from 2637 Hz (an E) all the way down to 1661 Hz (a G#). At the colder temperature, it becomes possible to hear the separate wing strokes because he’s moving more slowly. He’s cold, but determined!

Here’s another example: a Jumping Bush Cricket on a warm, late-summer evening and then a chilly night (55F). As they sing slower (as well as lower in pitch), it becomes possible to better hear the individual wing strokes that make up each chirp.


This Pine Tree Cricket was struggling to sing when the night temperature dropped from 70F (beginning of this track) down to 61F (end of this track). Eventually, he could no longer continue his steady trill. He finally just stopped.

Finally, I have one last cricket/bird pairing to summarize. Remember that Four-spotted Tree Cricket recordings I paired with Field Sparrow?  The Four-spotted sings a continuous trill, but notice that it’s lower at the cooler temperatures and higher at warmer temperatures. The Field Sparrow (a species that would live in the same habitat as the Four-spotted Tree Cricket) has a song that can start lower and ascends. In just one song, the Field Sparrow covers the range of pitches that the Four-spotted sings at 66F all the way up to the 80 degrees. Birds can change pitches within a single song AND their pitches do not change with the temperature.

Our challenge is clear. Each song has just one pitch, but everyone’s pitches rise and fall together with temperature changes. We can’t assume that a recording of a particular cricket will match that same species in the field unless the temperatures are the same.  Rhythmic patterns are very helpful, so tree crickets that sing long, continuous trills are the biggest challenge. In future posts, I’ll offer more specific guidelines for these identifications when we talk about seasons and habitat.

                                Four-spotted Tree Cricket singing in aster flowers.

Sunday, February 25, 2018

Instruments and performance techniques: how crickets and katydids make their songs

Rattler Round-winged Katydid

This is the season for the early spring birdsong and maybe even the earliest frog songs. So why am I creating a post about cricket and katydid songs when we're still a month from the spring equinox?

It's not just my impatience for singing insect season. I’ve already written a number of posts on early-season bird and frog songs that have included species comparisons and how to listen. Yet I seldom seem to get a chance to include song comparisons for singing insects. Why?  Because I'm out in the field so much during their season of song, inevitably creating a collection of recordings and photos that take months (or longer) to edit.

So I've decided to write those listening skills posts now. You’ll know where to review them later in the year, and eventually, they will be part of a much larger project. You can always  check the blog sidebar for my previous posts on early spring singers, and I keep a list of upcoming programs there as well. And remember, the first Spring Field Crickets will begin singing in May. That’s not so far away, is it?


“What happened to all the crickets?" 

"Why are there no crickets this year?”

Every June, posts of great dismay about the abnormal absence of singing crickets will inevitably appear on Facebook and elsewhere. What people don’t realize is that June is simply too early for all but a very few species of crickets or katydids to be singing in our area and regions similar to ours. No need to panic; they just haven’t matured yet.

Almost all of our singing insects overwinter as eggs, which is why we don’t hear most of our crickets and katydids until later July or August. They literally have to grow their instruments.

Here’s a photo of a katydid nymph. Do you see any wings on this little one? 

Amblychorypha katydid nymph

Now look at an adult from the same genus. He is absolutely prepared to sing!

Rattler Round-winged Katydid adult

Cricket and katydid instruments are at the base of their upper set of wings (the tegmina).  One wing has a file at its base and the other has a scraper. They move their wings across each other at a very high rate of speed and do so either continuously or in short bursts, creating either long, steady trills or a rhythmic pattern of shorter songs. 

A katydid’s left wing, which has the "file," crosses over the top of the right wing, which has the "scraper" that extends upward to the file.

 Gladiator Meadow Katydid: left wing over right

In contrast, a cricket’s right wing crosses above and over the left wing. 

These insects also have an additional set of flight wings beneath the tegmina, though some species don't actually fly. This lower set of wings is not involved in song production.

Some katydids have short – or even very short – wings, yet  they still can generate sound. Here is an adult Straight-lanced Meadow Katydid - look at those tiny wings!

Let’s also take a look at these insects' wing positions while singing. There’s quite a bit of variety, and I think you'll find this to be helpful information in the field.

Tree crickets are the most dramatic. A male tree cricket holds his wings against his body until he’s going to sing. 

Broad-winged Tree Cricket

Then he raises his wings until they are perpendicular to his body. At this point, the file and scraper are in position to create a song that's surprisingly loud for such a small insect.

 Broad-winged Tree Cricket singing

What if they could broadcast their songs to interested females even more effectively with additional amplification beyond that of their beautiful wings? In fact, some tree crickets use the lobes of a leaf, two adjoining leaves, or even a hole in a leaf to create a larger surface that amplifies their songs.

Narrow-winged Tree Cricket

Narrow-winged Tree Cricket

Snowy Tree Cricket

 Snowy Tree Cricket

 Davis's Tree Cricket

Davis's Tree Cricket

Ground crickets and field crickets don’t raise their wings as high as the tree crickets, and they generally sing from hiding places. 

 Allard's Ground Cricket singing on a fallen leaf in the sun

They may use anything from cracks in the pavement to rocks in a garden or drainage area to create resonance for their songs.

Fall Field Cricket singing

Some sing under leaf litter on the forest floor and others from deep within a clump of grass. We may not see them, but we can certainly hear them.

Jumping Bush Crickets and Handsome Trigs raise their wings higher than ground and field crickets and will sing from twigs, leaves, branches, and even hidden within a curled-up leaf. 

 Jumping Bush Cricket revealed

 Handsome Trig sings from his hiding place

Unlike many of the cricket species, katydids don't raise their wings much above their bodies. Depending on the species, katydids can sing from a grass stem, a tree branch, the top of a wildflower like Joe Pye, a shrub, or from cattails.

Common True Katydids sing up in the trees. Between their incredibly leaflike wings and their location well above our heads, we don’t often have the opportunity to observe their performances. On one of my public singing insects walks at Lake Metroparks’ Environmental Learning Center, however, two participants spent 30 minutes searching for a singer they were certain was right above their heads. Their persistence paid off: here he is!

Common True Katydid

Let's look next at three of the meadow katydids in the genus Orchelimum. Black-legged Meadow Katydids often sing from cattails or bulrushes in wetlands. They prefer a thick stem for a solid, secure singing perch.

Black-legged Meadow Katydid

Their early summer relatives, the Gladiator Meadow Katydids, sing from grass stems such as reed canary grass (an invasive non-native plant that does happen to provide the required amount of support). They may even sing on a timothy (pasture grass) seed head, where they will also enthusiastically dine on the seeds.

Gladiator Meadow Katydid

In upland meadows, their Common Meadow Katydid cousins sing from grasses and wildflowers in drier habitats.

Common Meadow Katydid

All three of these meadow katydids raise their wings just enough that we can observe the rapid wing movement.  For an example, please see Wil Hershberger’s Black-legged Meadow Katydid video on The Songs of Insects here.

Smaller meadow katydids from the genus Conocephalus seem to barely raise their wings at all, but you may still be able to observe their songs if you’re close enough.   
Short-winged Meadow Katydid singing

The songs typically consist of some initial “tics" immediately followed by long “whirrs,” so watch for what appears to be rapid vibration of the wings. At times, the visual clues have been my only confirmation that I should turn on my recorder, as the songs are very high and soft to many human ears. Close observation was very helpful when recording this Black-sided Meadow Katydid, as I couldn't even hear him singing with the louder Black-legged Meadow Katydids nearby.

Black-sided Meadow Katydid singing on a cattail

The larger katydids that are such impressive leaf mimics generally have songs consisting primarily of a series of percussive “tics.” You may be able to see their subtle, almost horizontal-appearing wing movement, but as with meadow katydids, the wings will not be raised very high. Songs will appear more like wing flicks than long vibrations. 

Bush katydids (genus Scudderia) will climb up to the tops of flowers and sing from these elegant stages at night and occasionally in the late afternoon if the nights are too chilly. I find females there as well.

 This Texas Bush Katydid (above) used these asters for his afternoon performance.

This Curve-tailed Bush Katydid female (below) was walking across the tops of the 
goldenrod flowers. A singing male was nearby - a lovely location for a romantic evening..

Rattler Round-winged Katydids and Oblong-winged Katydids may sing from a leaf that provides a small platform stage. Greater Angle-wings, however, will generally sing in trees or the tops of tall shrubs.

 Oblong-winged Katydid

Conehead katydids have longer rattling or buzzing songs. If your high-frequency hearing is intact, they may seem almost annoyingly loud. If those frequencies are less apparent than they once were, you may have difficulty hearing some of these coneheads because their songs are quite high - typically above 10,000 Hz. 

Sword-bearing Coneheads typically sing from plants that have a stems heavy enough to support these sizable katydids. Their wings are somewhat raised and their rapid, vibrating songs will be visually apparent. They frequently seem to stroll around their plants, alternating between upside-down and right side-up positions while they sing.

Sword-bearing Conehead

Nebraska Coneheads will additionally sing from shrubs as well as thick, sturdy plant stems, as they are often found near woodland edges or in isolated shrubs in a meadow. 

 Nebraska Conehead singing

Coneheads can often be observed singing, and insect song hike participants invariably consider the discovery of a concertizing conehead to be the highlight of the evening.

Sword-bearing Conehead walking while singing

Future posts will include comparisons of species with similar songs so that you can begin to separate the singers in night chorus. Another very helpful guideline will be a description of songs by habitat: who sings with whom in various NE Ohio's meadows, marshes, woodlands, and shrubby edgres and fields. I'll also create a timeline of which species sing in early summer through those that sing until a hard frost.  

As with birds, not everyone sings simultaneously or in the same location. Once we can narrow down the choices for a particular time and place, learning the singers and their songs becomes considerably easier!