Monday, August 22, 2016

Night noises

By Beth Sullivan
After an unbearably long period of heat and humidity, it has been wonderful to finally shut off the AC and open the windows at night. What a change from just a week or so ago. What a racket!
The volume of sound, the chorus, is a bit like stepping into the middle of a swamp of Spring Peepers. But the Peepers have long ago quieted and left the breeding ponds. The Bullfrog may bellow in the swamp, and Gray Tree frogs will sing before a rain. Occasionally the light and temperature in September will confuse a Peeper into singing a bit, but the chorus is gone.
Spring Peepers have ceased their chorus.

Bull Frogs bellow out in the swamps throughout a hot summer night. Photograph by Al Bach.

Noisy insects

Now is the season of insects. Through the summer the insect population has swelled. They have eaten and grown and multiplied. The majority of the millions of species of insects on Earth are silent. But for those that are not, this is their time, and they are a making a loud noise in the summer night. Like birds, it is mostly the males that do the calling; they do so to declare territory and to find mates. But unlike birds, their song is not created vocally but with other body parts.
You may hear a Dragonfly whir by but they make no real noise.

Almost all the noise we hear from insects at this time of the season, is made by those of the genus Orthoptera-the Ortho meaning legs-and are familiarly known as Crickets and Grasshoppers, with impressive back legs. As adults now, these insects have developed wings. Not all are good fliers, but they make great music. By vibrating and rubbing ridged segments of their wings against one another, they create a variety of high pitched sounds. They hear one another by means of “ear drums” on their front legs. Unless you have had one of these insects stuck in the house, it is hard to single out one song. It is the combined efforts of millions of these insects that makes the ringing tones we hear now.
The easiest song to identify is made by the Katydid, which is actually a long horned grasshopper. The good sized insect has a flattened body of bright green, making it appear like a leaf on edge. Long hind legs allow it to leap, and they do fly when in danger. But they are nearly impossible to see, as their camouflage is perfect. Their song is the distinctive, low toned “Katy-did” “Katy did-n’t”. Repeated over and over.
When on a leaf, the Katydid is impossible to see. Photograph by Bruce Fellman

We all know of the common Field Cricket, black with brown wings folded over its back. They are the easiest to find in woods and gardens and paths in fields. Kids love to find and contain the black field crickets, but let one loose in a house, and you will become familiar with the song very quickly.
Field Crickets are found in woods and fields.  Photograph by Al Bach.

Small, delicate, and very loud

The ones that seem to make the highest, most consistent buzzing/ringing sound on summer nights are the Tree Crickets. These are small and delicate. With lacey wings, they are high in trees, up in bushes and in grasses. Their fast-paced and high pitched chirping is created by wing-on-wing motions. These create chirping noises that actually increase in frequency the higher the temperature. Some people believe you can actually deduce the actual temperature by counting the cricket chirps and applying a mathematical formula. If you can possibly count the chirps.
A Tree Cricket is small, rarely seen, and most frequently the noisiest. 

Of course with the windows open, we are also treated to the hooting of owls, yip and howl of coyotes, the occasional Gray Tree Frog and once in a while, the scream of a Fisher. That’s enough to break the peaceful hypnosis that comes when listening to the chorus of night insects.

Photographs by Beth Sullivan unless otherwise indicated.

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