Mediterranean Pyrenees
  • Home
  • About
  • Galleries
    • Birds of the Mediterranean Pyrenees >
      • Common Birds of the Mediterranean Pyrenees by Isobel
    • Weather in the Mediterranean Pyrenees >
      • Weather: skies and storms in the Mediterranean Pyrenees
      • Clouds above the Mediterranean Pyrenees by Isobel
      • The summer of 2015 by Isobel
    • Bruce's Pix >
      • Beetles, Bugs and other insects
      • Birds
      • Butterflies
      • Butterflies of La Batère
      • Canigou
      • Castles
      • Dragonflies
      • Flowers
      • Pyrenees Landscapes
      • TGV
      • UK photos
    • Isobel's Images >
      • Isobel's favourite images
      • Springtime in an Alberes garden
      • In the garden
      • Tour de Batere, spring 2015 with Robin Noble
    • Lesley's Snaps >
      • Insects & Arachnids
      • Bees
      • Birds
      • Les Albères
      • Elsewhere in the region
    • Robin's Photos
    • Martine's Photos
    • GUESTS' Gallery
  • Birdsong
  • Blog
  • Resources
  • Contact

Another Crayfish!

17/6/2016

0 Comments

 
 by Lesley McLaren

I keep my dog on the lead for a heap of reasons, one of which is that he's an obsessive hunter. I would be unlikely to find him ever again if he were free to chase the wildlife that we sometimes come across. Nor would it be good for the animals and birds. But inevitably he stops to sniff the undergrowth - to check what's passed this way, to add his mark, and frequently to snatch up and gulp down something foul or rotting. The Find For Today, in the verge above a ditch between nectarine orchard and vineyard, was a dead crayfish. I'd stopped to watch swifts zoom past at eye-level, and was astonished when I next glanced down and saw a big red claw sticking out of his mouth.

After having bumped into a live one at the beginning of the month, to come across another, once again far from water, made me wonder what was going on. Had it been dropped by a predator, as suggested in a comment on my last blog? Or is their habitat more varied than I imagined and they can survive in ditches that are dry for most of the year? Or do they wander - especially after heavy rain? I've never seen them here before, but we have had more rain than usual this month.

Yesterday's thunderstorms left Mount Canigou with another powdering of snow - something I don't remember seeing mid-June before. Nor can I recall the countryside (or my garden) looking quite so lush at this time of year. The wildflowers have been spectacular - the scent of broom almost overpowering at times - and some grasses in verges, hedgerows and untended fields are now as tall as me! Perfect conditions for crayfish?

Time to find out more about them.


My dog's breakfast was the same species as the one we found a couple of weeks ago.
I remembered having noticed, when I first looked it up in my book on Albères flora and fauna, that it's considered "invasive". And its common English and French names (Red Swamp Crayfish/Écrevisse de Louisiane) give a clue as to why this is. Another case of human interference backfiring.

After surfing the net when we got back home this morning, I now know that these Southeastern USA and Mexican crayfish were introduced into several European countries in an effort to replace diminished stocks of our own native species. But as so often seems to happen with such programmes, there were escapees from farms, and some were released from aquaria. Others will indeed have been dispersed by birds such as herons.

Fascinating to discover that they are good climbers and can walk many kilometres overland, in search of water. (Sources differ as to distances - from 3 to 17km!) They can also survive long periods of drought by burrowing deep into riverbanks and ditches.

And in the breeding season the males go walkabout. Aha!

So perhaps the two crayfish I've seen have been males, and the live one knew exactly what he was doing that day I came across him. Or thought he did. It looks as though he (or another one) didn't make it after all, because the postscript to that story is that a few days later I (or rather my dog!) found an empty shell very close to where we first saw it (which was on the narrow track, bottom right, of this corner between vineyards):


Picture
Perhaps it took a wrong turn, got caught up in all that long grass, and baked in the sun. Or perhaps someone else's dog killed it.

Part of me had been feeling bad about having decided to let nature take its course and not try to help that one reach water (even though I only had my hat in which to carry it!). But now my conscience is much clearer. Because not only was he wandering of his own accord, but he and his kind are having a seriously negative impact on our ecosystem.

I've learned that they can breed in their second year, and females may lay up to 600 eggs at a time. In warm regions like this, there may even be two breeding cycles in twelve months. They are resistant to, but can transmit crayfish plague to our native species, the rare White-clawed crayfish/Écrevisse à pattes blanches. And all that burrowing can cause river banks to collapse, and can reduce clarity of water bodies, which in turn encourages the growth of certain unwanted algae. They are omnivorous and are implicated in the decline of some plant and animal species in some areas.

So what eats them?

I read that studies in Spain and Portugal show they are naturally predated by fox, otter, heron, stork, and some fish - including pike and bass. While this will help keep their numbers in check, it's alarming to discover that red swamp crayfish accumulate heavy metals, which can poison their predators.

Unfortunately, even had I known this last fact before today, I wouldn't have been able to stop my dog crunching up his find. All I can do is hope that just the one won't do him any harm.


None of this is the crayfishes' fault of course. It's all down to us. Nevertheless, although pleased to have solved the mystery of their appearance on land, I do see them in a different light now.

There's a different light outside the window too, as I end this blog. Another thunderstorm approaches. Will it spark more wanderings?

Postscript 18th June:
YES, is the answer to my last question. This morning, as I drove down to the orchards and vineyards, I had to stop for one crossing the road. In view of what I now know about about them, perhaps I should have run him over. But mosquitoes are about my limit when it comes to cold blooded murder. Trouble was, when I stopped he stopped, which made me feel obliged to get him safely out of the way so no one else could crush him either. Now my conscience is totally confused.

Picture
Quite a whopper! And very aggressive. He certainly wasn't about to let me pick him up. In the absence of a net or long stick, in the end I used my phone to kind of flick him into the grass. He wasn't impressed and continued to lunge at me afterwards, while I took this video.
0 Comments

Late Spring Seabird Blog

17/6/2016

0 Comments

 
by Robin Noble

The constantly changing weather is making planning ahead quite difficult, but the sea is definitely warming up, and so the boating season is firmly underway. I have remarked before that I do not understand why we should have so few seabirds (although there seem to be more gulls about this year), when there is certainly no shortage of fish. However, from time to time something interesting quite literally appears on the horizon.
 
We were out one day last week when we saw a low, planing flight over the sea, dark against the sombre water on a day of oily calm or occasional slight swell. It was immediately evocative for both of us; we are familiar with the manx shearwater which nests on the dramatic island of Rum in the Small Isles off Scotland's West Coast, and this clearly had to belong to the same family, which includes the bulkier fulmar with which some readers may be more familiar. We went in the direction of the bird we had seen, and as we got closer, it turned out that there were, ultimately, six of them, as well as one immature gannet; this was, interestingly, often followed by one of the other birds.
 
As we got nearer and switched off the motor, the birds began to circle around the boat at intervals, and it became clear that these were definitely shearwaters, but of a type we had not seen before. They were perhaps larger, at least longer-winged than a fulmar, but much slimmer, more like a larger version of the manx, but definitely brownish on the back and wing. There was also a conspicuous, narrow, white band above the short, dark tail, and the birds had a dark cap above a pale throat and white breast. Having noted these main characteristics, we sat entranced, as they flew around us, skimming the surface of the sea in a long, low, undulating flight. We could see quite clearly the complex tube-nose which all members of the petrel family possess, from the tiny storm petrel to the mighty albatross. I have recently read that it is now thought that this characteristic nose helps the bird gauge the air pressure as it passes over the waves.
 
Once home, it was out with the books and we were surprised how many possible candidates there were, including the balearic and Cory's shearwaters. But although the former are clearly rather more "local", we decided eventually that these were definitely the great (or greater!) shearwater, which really belongs to the Atlantic. Looking carefully at the illustrations, I have come to the conclusion that these were immature birds, non-breeders. The petrels do not breed until they are perhaps eight or nine years old; several of them seem to live to be at least forty. In those first years, they range all over the oceans of the world, and our birds had clearly opted for a Mediterranean break - and who can blame them?



0 Comments

Surprises in the Vineyards

1/6/2016

2 Comments

 
Picture
by Lesley McLaren

While walking my dog through the vineyards this morning, my thoughts turned to the peculiar looking mole cricket I came across the other day (only the second I've ever seen).






















These scuttle rather than fly, and burrow (hence the name), to find their preferred delicacy: vine roots. And I was thinking about how, at first glance, their front feet resemble lobster claws ...
when I looked down and saw, walking towards me on the grassy track ...

A lobster.

Was I hallucinating?

No. Roughly the size of my hand, it was, in fact, a crayfish. I know there's been an unusual amount of rain for the time of year lately, so the grass is long, lush and damp, but even so, this was something of a surprising find - about half a kilometre from the nearest pond or stream.

Unfortunately I didn't have my camera with me (only my phone) but to prove I'm not kidding:


Picture
When I got close it reared up - balancing on its tail tucked underneath - pincers poised in a convincing threat to grab my dog's nose should he be tempted to investigate, or my finger should I try to move a blade of grass out of its face to get a better shot.

If I moved round, it moved too so it continued to face me, maintaining that intimidating stance. Only when we'd retreated a few feet did it relax and continue on its way. It'll have a long walk to the nearest watercourse, but I hope it makes it.

Picture
2 Comments

    Authors

    Bruce Hyde
    Isobel Mackintosh
    Lesley McLaren
    Robin Noble

    Archives

    August 2020
    May 2020
    September 2019
    August 2019
    July 2019
    March 2019
    February 2019
    September 2018
    August 2018
    July 2018
    May 2018
    April 2018
    March 2018
    January 2018
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    March 2015
    February 2015
    December 2014
    October 2014
    September 2014
    August 2014
    July 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    December 2013
    November 2013

    Categories

    All
    Amphibians
    Arachnids
    Birds
    Bruce Hyde
    Dragonfly Differences
    Insects
    Isobel Mackintosh
    Lesley McLaren
    Mammals
    Marine Life
    Misc
    Mushrooms & Fungi
    Plants
    Reptiles
    Robin Noble
    Sea & Coast
    Tracks/Traces
    Weather

    Click icon for notification of new posts
    Subscribe
Lesley McLaren, Bruce Hyde, Isobel Mackintosh, Robin Noble, Martine Howard, mediterraneanpyrenees.com associates and affiliates do not warrant or assume any legal liability or responsibility for the accuracy, completeness or usefulness of any information, product or process disclosed. Lesley McLaren, Bruce Hyde, Isobel Mackintosh, Robin Noble, Martine Howard, mediterraneanpyrenees.com and affiliates do not endorse or recommend any commercial products, processes or services and cannot be held liable for any result of the use of such information, products, processes or services discussed on this website.