Five intrepid orthopterists met by the footbridge at the alloted hour to see what orthopteran delights the site held in store for them. The weather was warm and sunny, just right, and a great improvment on the rain that cancelled the Wednesday walk.
As usual the first insects were searched for by the bench, at the top of the steps. Here we very soon found Meadow Grasshopper, Field Grasshopper and Long-winged Conehead. Attention was drawn to the pronotum on the two grasshoppers so that the differences in the two species could be seen. I managed to persuade a Long-winged Conehead to sit on my finger so that everybody got a good view of one.
The other main target was the Roesel’s Bush Cricket, which prefers the banks around the Deep Pit, so we set off along the south side of the Slurry Lagoon. As we progressed, opposite the railway embankment, the path was beside a wide grassy area where more Meadow and Field Grasshoppers were seen. In the brambles at the top of the bank a Spiked Shieldbug Picromerus bidens was found and several hoverflies, including Helophilus trivittatus and Sphaerophoria scripta. Further on, as we passed the Deep Pit there were Common Blue and Small Copper butterflies to see.
We were fortunate to have one member of the party who could actually hear the crickets stridulating (We have tried ‘bat boxes’ but they are non directional and frustratingly tell you there are crickets about but not where they are.), its normally a good idea to have some kids in tow to do this for you. Soon there were Roesel’s Bush Crickets being found by the bucket load. They were mainly at the top of the grassy bank as we looked towards the gravel pits and we were soon getting excellent views of them.
With the excitement of seeing so many crickets, the walk leader forgot to search for Slender Ground Hoppers, which are fairly common on the site and often found on the edge of the Small Gravel Pit. Other than that the group had an enjoyable walk and were well pleased with the insects that they had seen.
Six people turned up for this walk, despite the threatened rain. As they collected by the foot bridge first a Migrant Hawker flew overhead and then a Southern Hawker came to check us out, before settling on the hedge. It was mainly green and black but the blue on its last two abdominal segments showed it to be a male.
We entered the reserve and went up the steps to the seat. Just by the seat we found the first Long-winged Cone-heads and soon had one in a viewing pot for everyone to see. Although superficially like a grasshopper the incredibly long antennae suggested its true affinity to the bush-crickets. We then caught our first grasshopper with much shorter and thicker antennae and were just getting to grips with its pronotum when the first shower struck. The group dived under the nearest bushes and tried not to get too wet, peeping at the glowering sky from time to time and saying encouraging things like, ‘It’s getting brighter over there.’, ‘I think it’s slackening off.’. When we were all soaked the rain stopped and the sun came out. We identified the grasshopper as a Meadow Grasshopper by the shape of its pronotum, which is the armour like scales that cover its neck and shoulders.
As we walked along to the Causeway the sun warmed our backs and we began to dry out. On the Causeway we located several Roesel’s Bush-crickets, but could not actually see any. Three of our company had ears that could hear them, but the frequency was too high for the rest of us so Alan got his bat detector out and soon pointed out two or three. They are very hard to approach and tend to go silent long before you are close enough to see them. The distinguishing mark on the Roesel’s is a yellow line all the way around the border on the side of the pronotum, but we were unable to point this out. However we did manage to connect with another species of grasshopper, the Field Grasshopper. Again it is the pattern on the pronotum that gives the most significant clue to its identity, followed by the fact that it has a hairy chest. We now began to realise the difficulties involved in identifying grasshoppers as we found several small chestnut brown ones. These were assumed to be nymphs although they were seen to be stridulating like the adults, one even seeing off a much larger adult Field Grasshopper. The pronotums on these nymphs were not well developed or marked so they gave few clues to the species. The other problem with identification is the fact that the same species of grasshopper comes in two or three different colour ways and all can be present on the same site.
We dried out in the sun as we struggled to get to grips with orthopteran identification and were all completely dry when the next menacing black cloud sailed overhead. ‘It won’t rain on us.’ and ‘Look its raining over Carlton’ soon gave way to ‘Let’s go to the railway bridge’ and ‘Run’. The front-runners made it to the bridge still dry but the rear guard were soaked as they staggered through the downpour into the shelter. Even the swallows were staying on their nesting shelves under the bridge. Coots were diving by the bridge and surfacing with large round items in their beaks, surrounded by a screen of water droplets as the raindrops bounced and shattered on the river surface around them. I wished I had a camera with a telephoto lens. Soon the rain abated and we came out from under the bridge. We were just about to go up the steps by the Deep Pit when a Whimbrel called as it flew overhead on its way to the south. This encouraged us to go to the Causeway again so that we could see if anything else had been brought down by the rain onto the Slurry Lagoon. We found three Wigeon that had not been seen before the rain but nothing else. The grass was quite wet now and it was noticeably cooler so that there was little insect activity to detect so we called it a day and went home, having identified four orthopteran species.