Wild Side: Listen for chirping

The jumping bush cricket is here for the duration.

0
A male jumping bush cricket, Orocharis saltator. This particular one got into our bedroom back in August, and its calling made it impossible to sleep until I found it and reintroduced it to the great outdoors. — Matt Pelikan

As we move into November, there is almost always a dramatic shift in the weather on the Vineyard, and with that, a shift in what wildlife is around. We can no longer pretend that autumn is just beginning. And around us, leaves drop, the migration of songbirds tails away, and the chorus of calling insects fades.

It was a poor season for many kinds of insects. Our deep, prolonged drought stressed the plant life that many insects depend on for food, and by late summer, insect life (most notably but not only butterflies) had grown relatively scarce. My favorite group of insects, the Orthoptera, also suffered this year: Numbers of many species of grasshoppers and katydids were far below what I usually observe.

One notable exception to this rule, though, continues to sing every night in our Oak Bluffs yard. The jumping bush cricket, Orocharis saltator, didn’t just manage well during the drought — it appeared to expand its distribution on the Vineyard, continuing a trend that has been evident since I first found this species on the Island.

Like many other crickets, Orocharis is far more likely to be heard than seen. Males call in a chorus, each contributing a series of short, rich trills perhaps a half-second long and spaced a second or two apart. As far as I can tell, each male calls on a slightly different pitch, so the chorus has an oddly dissonant effect.

The species calls mostly at night, though they can be active during the day as well. While most sources suggest that jumping bush crickets prefer deciduous vegetation, on the Vineyard at least they often associate with evergreens: red cedar, arborvitae, and pitch and white pines. The association with woody vegetation may have helped this species during the summer’s drought: With deep root systems, trees and shrubs often can reach groundwater that grasses and flowers can’t, staying healthy when less long-lived plants are stressed.

Regardless of the plant type they’re on, these crickets tend to perch on twigs and branches, where their brownish coloration blends in perfectly, rather than on foliage. I think they often hang from the underside of branches, making them hard to spot. It’s possible to get close to a calling Orocharis, but even when you’re within inches, you usually won’t see it. And then you’ll move a bit too close, and your quarry will abruptly go silent.

Fortunately, the call of this species is loud and distinctive, and it has a habit of occasionally coming in to visit porch lights. A happy result is that a recent northward expansion by this species, probably driven by climate change, has been unusually well documented. Formerly found no farther north than the New York City area, Orocharis seems to have first been documented in Massachusetts only within the last 10 years or so. Once arrived, it spread explosively and is now a common species, at least in parts of mainland Massachusetts that I’ve visited recently.

It probably arrived on the Vineyard recently as well. I expect its arrival was human-aided — perhaps these crickets were imported on landscaping shrubs. The species has full wings and can presumably fly. But it’s hard to imagine such a chunky insect making it here under its own steam.

My own records don’t pinpoint the arrival of Orocharis very well because I was hearing this species for several years before I figured out what it was! The first time the mystery caller appeared in my field notes was August 31, 2016, when I noted “a short, pulsed song — each pulse considerably shorter than a second in length, with the pulses very regularly spaced — calling around the house.” But, assuming that we are too far north for Orocharis, I misidentified it as a tree cricket of some kind.

Two years later, an Orocharis perched on one of our window screens put this species on my radar and led me to realize what I had been hearing. As on the mainland, jumping bush crickets rapidly spread once they arrived here, primarily in settled areas but also sometimes in natural habitats. This cricket does very well in landscape plants around houses, and there are few residential areas on the Vineyard that don’t have this species now.

As the weather cools in late October and early November, Orocharis gradually grows less common. The song changes, too, in colder weather. Each chirp slows down, so you can hear the individual pulses more clearly (it sounds a lot like the noise you get running your finger along the teeth of a hair comb). The chirps last longer and grow more widely spaced. By mid-November, my records suggest, the species will have gone silent until next year. Eggs laid this past season will hatch and the new generation will mature and begin singing in August sometime. Stay tuned!