At the time Lesley was seeing her crayfish, we had gone down to the Emporda to spend a day at our favourite Nature Reserve. Every time we go, it is different, and once again it gave us a lovely and interesting day. Because of all the rain earlier in the year, it was remarkably lush, and walking one or two of the paths between the lines of trees, we were almost assailed by birdsong. Some we do by now recognise, like the Cetti’s warbler, but there were many others we did not know, and in the dense and humid green, it felt rather as I imagine Costa Rica to be, strange, exotic and full of birds. But there was one loud and constant call, which belonged in my mind elsewhere. This was the song of the common cuckoo, known from English copses or highland birchwoods, and not much heard by us in the last few years. But for us, it has been a year of cuckoos; I have heard them on the hill behind our house, and frequently again on a recent trip into the high Pyrenees.
It had obviously rained during the night, and as we walked a track from one hide to another, I saw a few quick movements in one of the puddles, and we stopped to look. The water was a bit muddy, and it took a while to get a reasonable view of the little creatures in this rather unlikely and limited habitat. They were clearly small crustaceans, perhaps a maximum of two inches long, with a little reddish-pink on the body, otherwise a dark grey. They were lively, and when we provided shadow, prepared to leave the water and venture on to the open track. One decided that Martine, who was photographing it, was an enemy, and adopted a fierce and defensive stance, claws menacing and wide – if rather diminutive.
We wondered what exactly they were doing there in this somewhat ephemeral habitat, but decided to leave them to their own devices and followed the track further to where it crossed a small, rather cloudy brook. While Martine tried for the perfect shot of a stork in the green meadow, I took a few snaps of the water, as I have always loved dark green pools under trees. While I was thus engaged, and therefore watching the water, I realised that there were more, much larger crustaceans, some half-hauled out on thin branches; the reddish colouration was clear on a few.
Of course, when we got home and read Lesley’s blog we realised that these were her crayfish, and, presumably, their young – perhaps in the spring even the young are highly mobile on land, especially if it is damp ground. In fact, it turned out that at the back of the Nature Centre itself, there is a pond, which contained some more of these creatures, which we could very easily observe. Martine added to our scanty knowledge of them when she saw one attack, kill, and start to eat a smaller one – so they are apparently cannibals!
The latter fact might be of some comfort to those who, understandably, are worried about the impact of these foreign species on the native amphibians and so on. While I know why folk are worried, I wonder whether in the longer term, we are right to be so concerned. Nature is far from static, and there is really no definitive list of creatures which belong to one location or another; creatures have come and gone, moved in and out, throughout history and before that, and, of course, many have become extinct, locally or internationally, during the course of time. That does not mean that I disapprove of efforts, for instance, to trap mink in Britain, in order to assist the populations of water-voles. Mink are very versatile predators, almost omnivorous, and therefore, very successful. If the crayfish are similarly rapacious, then efforts to catch them are obviously worthwhile – perhaps we missed a trick? I will have to check Lesley’s blog to see whether they taste good!