Wednesday, 13 May 2020

Wednesday - (hopefully) provisional

Well, the first day of being encouraged to spend more time outdoors and, so far, no reports from any observers. For now just the meagre fare from my brief checks (MD).
This is the second year running this Grey Wagtail has bred at Crawshawbooth East Lancs. See last year’s Heysham report for ringing details.  Photo today with fledged young.  Thanks Craig

Hopefully more later.

Heysham skeer low water 11:00
Great Crested grebe 3
Ringed Plover 1
Whimbrel 3
Curlew 1

Heysham Head high cliffs
Rock Pipits - the two territorial birds very active

Lighthouse area high water 16:40
Whimbrel 2 in
Dunlin 2 in
Knot 17 in
The Dunlin and Knot stopped for a rest on rocks before continuing in.

Something you might fancy checking if you walk along the water line at low water.
At this time of year, as the water starts to warm, the crabs start to shed their shells. Bear in mind that it not just the carapace that is shed, but the whole outer skeleton, including legs, claws etc.  The new shells, although soft for a couple of days, harden into a larger size, giving the crab room to grow in to, until they are ready to shed to the next size.

But things are different for hermit crabs.
These crabs have soft bodies with only a hard outer skeleton protecting the head, legs and claws. These have to be shed periodically. The ideal scenario for a hermit crab is to find a larger shell before they shed their protection. A large shell allows them to retreat right inside, out of sight, when threatened.
Unfortunately a larger shell is more cumbersome,  and they regularly end up stranded, but safe on the water's edge. There were several this morning:
The opening size shell is a periwinkle. 
If you pick this up the crab totally disappears

They then move on to dog whelk shells
This crab is quite small for this shell but it will last it for at least two sheddings

And finally a common whelk
This was not actually one of today's crabs. This one was stranded by the spring tides last week. At this size they cannot fully retreat into the shell. But the claws act as a very effective seal.

Of course all three of these shells come in various sizes. The three above are about as large as each gets. If you find any of these shells "empty" at low water line, the chances are a hermit crab will be inside. Place it on the mud hole side up, and the crab will reveal itself. But please return it to water or turn it over before you leave.