Everyone,
At 17h30 I went up to the culvert past the Pentecostal Church, to see if
any of the Cepaea snails that hibernate right at the edge of the ditch
there were active. I found only about a 15cm band of damp grass along
the water, below a bank dusty and pale with road sand, so I didn't have
much hope of seeing snails wandering around. In previous years we've
found that they move down the 3m from the edge of the road to hibernate
right at the edge of the water, under dead grass. I decided to pull up
the grass along the metre of the bank where we'd found the most last
year, but I only turned up a few dead shells along most of the metre.
But when I got to a little notch in the shore where I'd found some dead
shells last year, there were a lot of dead shells, and as I pulled them
out and felt further in, there were yet more shells. By the time I'd
pretty well come to the end of two 30cm burrows, about 6cm diameter, and
a big central chamber, about 10cm diameter and packed full of shells,
and a central burrow about 40 cm into the bank, I had about 2 litres of
shells, with a few living snails admixed. All were Cepaea nemoralis.
Some were mixed in with soil, and some were pretty clean. Some were
below the water level of the ditch, but most were above the water level.
most were adults, but there was a fair percentage of juveniles. Some had
pre-dated this winter, because they had the roots of herbs growing into
them. Aleta took pictures which will appear in a blog posting.
This certainly looks like the accumulated shells left by a predator --
but which one and how does it get the snails out of the shell without
breaking the shell? Blarina Shrews? Starnose Moles? Is this most of the
population along here eaten up, so that there won't be many this summer?
Is the mortality somehow the result of the soil's being unfrozen all
winter? There are certainly a lot of small mammal burrows revealed as
the winter-long heavy snow melts.
fred.
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Bishops Mills Natural History Centre
Frederick W. Schueler & Aleta Karstad
RR#2 Bishops Mills, Ontario, Canada K0G 1T0
on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
(613)258-3107 <bckcdb at istar.ca> http://pinicola.ca
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