Saturday 26 July 2008

The cricket season has started


Last weekend, at Knetishall Heath, I heard the steady reeling buzz of a Roesel’s Bush Cricket. To me, this signalled the start of the cricket season, prompting me to get out in search of other crickets and grasshoppers. Earlier today I found myself on the warren, not far from Brandon, in the company of Paul Stancliffe, another birder turned grasshopper enthusiast, and his two young daughters.

They say that as you get older so your hearing deteriorates and some of the first sounds to be lost are the high-pitched calls of grasshoppers and crickets. This is something that Paul had noticed the previous year, unable as he was to pick out the Roesel’s calling in the grass just outside of work. Fortunately, I can still hear the calls but quite probably not as well as Paul’s daughters. Paul had a trick up his sleeve though, a bat detector, which captured the buzzes and reels of the different grasshopper and cricket species and broadcast them at a frequency he could hear. By using this it was possible to distinguish the different calls, from the distinctive pulsating sound produced by the Striped-winged Grasshopper through to the strengthening buzzing chirps of Mottled Grasshopper which ended abruptly.

Working our way around the warren we encountered Field, Striped-winged and Common Green Grasshopper in the areas of longer grass. All three species were calling well and we netted a few to check on the identification features. Grasshoppers and crickets are a good group to get into; although there are not that many species, the variation in size and colour within a species ensures that identification is testing enough to keep you on your toes. In the areas of shorter breckland sward we encountered Mottled Grasshopper, smaller and more delicate than the other species we had so far seen but equally variable in colour (12 distinct colour forms are recognised). Some of the Mottled Grasshoppers were beautifully patterned, a mixture of soft greys and browns and perfectly camouflaged even on the bare ground.

The various grasshoppers go through a series of moults, increasing in size before they become full adults. We netted a fair few individuals that had not yet reached adult size, highlighting the fact that it was still early in the season. Other species that we might expect to find, such as Slender Ground-hopper, will not reach adult size until the start of August, so a return visit may be needed to pick these up. Searching for grasshoppers also tends to reveal a myriad of other small creatures, from beetles and shieldbugs through to solitary wasps and ants. It is tempting, though challenging, to tackle some of these more difficult groups.

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