While waders are the major bird group I have little to do with (I'm more a
passerine man!!) I suspect that with migration to breeding grounds younger
birds remain for a longer period and depart later (on average - they may
also form the majority of over-wintering birds, again for those anti-banders
banding is the only way or at least capture of birds is the only way of
answering this information, this isn't to say I condone leg flagging vs
colour banding!!!) than adult birds (breeders) - I'm sure there is a wader
expert out there to verify or comment on this hypothesis (banding data would
provide the evidence!!). I would suspect that the reverse may also be true,
i.e. younger birds depart later for their "wintering" grounds than do adults
- certainly northern hemisphere banding sites would have the data to confirm
this. Perhaps the early returners are early leavers (i.e. they squeeze all
their breeding effort into the same period of time but commence earlier i.e.
they are consistently early), alternatively they may have failed their
breeding attempt (e.g. nest predation, chick death) and thus have left their
breeding sites somewhat earlier. In any case there is bound to be natural
variation in departure times (both hemispheres) as a matter of course, it is
after all this variation is the basis for future evolutionary changes in
migration timing and sites.
Look forward to a wader experts point of view.
Cheers, Dean
From: Frank O'Connor <>
To:
Subject: Re: [BIRDING-AUS] Start of the Spring Migration [RFI from snipe
gurus]
Date: Mon, 05 Aug 2002 20:57:41 +0800
At 22:27 05/08/2002 +1000, Laurie&Leanne Knight wrote:
While I couldn't look them up in HANZAB today, I noticed a record from the
Birds
Aust bird observation site that a correspondent had commented about a
siting on
12 August 2000.
My question for the wader experts is, what is the earliest "spring" record
of a
Latham's Snipe in Australia, and do they fly directly to their austral
summer
haunts or in stages down the east coast? I suspect snipe heading to
taswegia
might stage, where the ones that set up shop in SEQ might come here
directly.
Are the snipe normally the first of the northern hemisphere migrants to
arrive?
I must say that I am highly impressed with their capacity to breed and
fledge
their young in Asia in time to get back to Aus just past the depth of
"winter" -
alright, we don't get a real winter in SEQ, but this is the best time of
year
for snow further south.
Does this early return mean that the snipe prefer Australia to Asia [you'd
think
they would spend longer in their breeding territory than their
non-breeding
territory] or could some sort of environmental change be motivating them
to rock
up earlier than usual?
Just a thought, but ...
Many first year waders (e.g. Red-necked Stint, Curlew Sandpiper, knots,
godwits, etc) don't return to breed until their second (or later) year.
For some waders the whole population seems to return (e.g. Oriental Plover,
Long-toed Stint, etc). However, the question is - Do the first year birds
breed when they return the first time? Or do they wait until they are two
or even three?
If the young birds do not breed, then could the non breeding snipe possibly
return earlier than the breeding population?
___________________________________________________________________
Frank O'Connor Birding WA http://members.iinet.net.au/~foconnor
Phone : (08) 9386 5694 Email :
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