Stephen, thank you for that reply. Even if you don't find the paper, I
shall have a good look at the sediments next time I'm out there. The
theory makes some sense. Just thinking, I don't think I have seen
shorebirds, even Beach Stone-Curlews, take adult soldier crabs, though
they take plenty of small crabs, which I always assumed to be immatures.
The big ones could probably do some damage to a bird's mouth as they
fight for survival. Also not good energetics.
Cheers,
Jill
Jill Dening
Sunshine Coast, Queensland, Australia
26° 51' 41"S 152° 56' 00"E
On 12/09/2010 8:55 AM, Stephen Ambrose wrote:
Hi Jill,
I remember reading a scientific paper a few years ago (sorry, I can't
remember which one) which said that juvenile soldier crabs tend to
congregate in large groups on different sediments to the larger adult
soldier crabs. If I remember correctly, the smaller soldier crabs tend to
congregate on the softer sands/muds (probably easier for them to excavate
these areas), whereas the larger ones can use sandflats/mudflats that are
more compacted and harder to excavate.
If I find the title of the paper I'll send it across to you.
Stephen Ambrose
Ryde, NSW
-----Original Message-----
From:
On Behalf Of Jill Dening
Sent: Saturday, 11 September 2010 4:59 PM
To: birding-aus
Subject: [Birding-Aus] Question about soldier crabs
Hi Everyone,
As I watched a Beach Stone-Curlew eating small soldier crabs on Friday,
it occurred to me that someone might have some knowledge about soldier
crabs.
My question is: do soldier crabs form creches? And if so, for what
purpose? And if not, why do they so frequently gather in these groups as
described below?
Many times over the years, and now again, I am watching some very large
soldier crabs gathering in large groups on the intertidal sandbanks in
Noosa, SEQ. At the same time, only metres away, I also see large
congregations of very much smaller soldier crabs, accompanied by a few
very large crabs. I know nothing about the life cycles of crabs. It has
always looked to me like the smaller crabs are being babysat by a few
large ones whilst the adults are off at a party. Well, that's the
anthropomorphic interpretation :-), but there has to be an answer.
Cheers,
Jill
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