I have slipped over the border on the basis of a tip-off, leaving Nelson’s county behind as I cross the river south of Thetford. A friend told me that he had heard them the other night as he drove along the road, windows down because of the sultry conditions. What he had heard was the stridulating song of the Great Green Bush Cricket, one of our most impressive insects. Adult Great Green Bush Crickets are chunky beasts, 4cm long in body and both large and loud enough to be worth a special trip over the border into Suffolk.
This particular colony is well known, close to the road and just across the river from the county boundary. Knowing they are here is one thing because, despite their size, they are not the easiest of creatures to spot. Despite the proximity of the road, there is something gentle and welcoming about this spot; the presence of a heron that lifts slowly out of the shallow water upon my approach and the controlled flight of hawker dragonflies. Beyond the small area of mown grass, no doubt maintained by the Environment Agency to retain access to the small weir, there is a wall of bracken which reaches to head height. It is in here that the crickets will be positioned, away from prying eyes and difficult to reach. I will have to be content with listening to their stridulations, not dissimilar to the more familiar Roesel’s Bush Crickets that stridulate outside work. Even this early in the afternoon there are one or two individuals in song and between the passing cars I can listen and marvel at such a cleverly constructed sound.
These are southern creatures, arriving here after the passing of the last glaciation they have been slow to spread north, highlighting their dependence on warm summers. Most populations are coastal and the species is distinctly local inland. They do not occur much further north than this and so they remain a tantalising colonist, not quite on my patch. Wasteground such as this, dominated with thistles and bracken, meets their needs and this scruffy patch provides ideal habitat.
I venture under the road bridge, working my way along the narrow ledge that sports the old remains of Otter spraints – a sure sign that they are doing well on the river and have ventured upstream from more familiar sites a mile or so distant. The cover on the other side of the road is less suitable, more heavily shaded and I soon head back under the bridge into the warmth of the fading sun to listen to the crickets for one last time. I should return one evening, torch in hand, to see if I can spot them.