Leg-flagging of shorebirds
Hi everyone,
I am the person within the Australasian Wader Studies Group (AWSG) who
collates all international flag sightings of shorebirds into a database. I
am responding to the concerns regarding leg-flagging of waders that have
been raised on Birding Aus (repeatedly) by Ian May.
First, can I assure you that there is still much to learn about the
migration of many (if not all) species of shorebirds, even though the data
generated from leg-flagging to date has already increased our knowledge
immensely. In the current edition of AWSG's journal, The Stilt, there is a
paper with the latest migration maps covering all of the common wader
species. This includes an explanation of what more has been learned over
the last five years, since the last similar report was published. All
issues of The Stilt are made available for free, online at the AWSG web site
www.awsg.org.au <http://www.awsg.org.au/> . However, there is a slight delay
between publication and uploading to the web site, so if you would like a
copy of this latest article, please email me for a copy.
I do not intend to enter into a debate about the pros-and-cons of
leg-flagging waders or banding more generally. Suffice to say, it is
regulated by the Australian Bird and Bat Banding Scheme (ABBBS) and through
research permits granted by the states. If there was any evidence of the
sort of adverse impacts from leg flagging that Ian May refers to, ABBBS
would most certainly, and immediately, ban leg flagging.
However, in contrast to Ian's claims, adverse impacts from flagging seem to
be incredibly rare.
I will put on the record some further information which might be relevant.
1) In response to these concerns (initially raised directly by Ian May with
Clive Minton, rather than via Birding Aus) AWSG did look in great detail at
the survival rates of small waders, including Red-necked Stints and Curlew
Sandpipers, with and without flags (i.e. those banded only with a metal
band, and comparing to those with both a band and a flag). There is no
detectable difference in survival. Other analyses of survival of shorebirds
cannon-netted, banded and flagged in Australia are consistent with similar
studies carried out in other parts of the world, in that they show
shorebirds (whether marked with metal bands, individual colour-band
combinations, or leg-flags) to be long-lived birds, with high rates of
annual adult survival.
Not only do flagged birds survive, they migrate and they get seen on
migration. The number of birds resighted on migration is limited by the
number of observers in remote places in the flyway, but when careful
searches are made, they usually result in fascinating data. Over the past 21
years, there have been over 21,000 resightings of Australian-flagged
shorebirds overseas. Important patterns are emerging from these resightings.
A recent example is the discovery of the importance of a small region in
Bohai Bay for subspecies piersmai of the Red Knot on northwards migration:
in 2009 it was used by 80% of birds flagged and individually colour-banded
in north-western Australia, and by 62% of those similarly marked in New
Zealand [1]. This site is rapidly being lost to tidal flat reclamation
projects, and current efforts to preserve it have been driven in large part
by the role that flag resightings played in discovering and quantifying its
importance.
In response specifically to the Great Knot and Global Flyway network
project, Danny Rogers has provided me with the following information: We
have done survival analyses on the Great Knots individually colour banded by
that project (with one flag and four colour-bands)... Average annual
survival of those Great Knots (i.e. the probablility of their surviving from
one year to the next) was 93.7%. There were some annual fluctuations
(especially a dip right after the closure of the Saemangeum sea-wall, which
is why we are analysing that data) but on the whole, Great Knots with
colour-bands are right up there with the longest-lived birds that have been
studied.
Also of relevance is that some species of shorebird which have never been
banded and flagged in Australia are suffering serious declines - one
particularly disturbing example being the critically endangered Spoon-billed
Sandpiper.
2) AWSG/VWSG always welcome volunteers to come and experience banding first
hand, and programs are published in relevant newsletters where possible e.g.
Birds Australia's VicGroup newsletter.
3) All banding studies (and most studies of any kind) do have impacts on the
study species, even though great efforts are made to minimise these impacts.
Regardless of how carefully you try and study something without affecting
it, it is impossible to do so. The individual banders, in conjunction with
the banding office, determine how best to minimise the adverse impacts on
birds and whether the scientific value of a study outweighs the costs. All
I can really say is that the impact of banding and flagging activities is
very minimal in comparison to the impacts of natural events and other human
activities on these species, and can not possibly be responsible for
shorebird population declines. Of course, many of the people banding waders
are also those most concerned about (and active in making a difference to)
their conservation status. They do this work out of a genuine passion and
commitment, and often devote more hours to this work than someone working
full time (but for no pay - and often at much cost). So it is easy to
criticise, but much harder to go out there and actually "do something
better".
On a much brighter note, some wader-flagging study projects in this flyway
have been implemented in place of shorebird hunting. So, for example, every
time I see a bird with black and white flags (indicating that it came from
Chongming Dao, an island near Shanghai in China) it is a tangible reminder
that these birds, which would once have been sold at local markets for food,
are now being released alive with colour flags instead.
4) AWSG focuses its conservation efforts on known threats to waders, in
particular stopping the destruction of their migratory stop-over sites.
This is an uphill battle, but having solid science behind the need to
protect these areas is critically important. As over half of the world's
population lives in 'our' flyway, development pressures are intense -
especially so in China and Korea.
There is an excellent article in a recent 'Wingspan' (Birds Australia's
magazine) which highlights the urgency of these threats, and the possibility
that existing bilateral conservation agreements (between Australia and
China, and Australia and Korea) could help stop or slow this destruction.
In their words "With a sustainable future for our shorebirds so imperilled,
it is vital that we take action and demand that our governments honour the
commitments they have signed up to at the international level". Read the
whole article at:
http://www.birdsaustralia.com.au/images/stories/publications/wingspan/Yellow
-Sea-article.pdf
It is always encouraging to see the common sense responses (and sometimes,
non-responses!) of many Birding Aus members, including those involved in
shorebird research. I hope that many of you will report your leg-flag
sightings in future - both to AWSG e.g. via our website
http://www.awsg.org.au/reportform.php and to Birding Aus. I hope that I
will be able to reply to you personally with useful information on the birds
that you see, and on how your sightings contribute to AWSG's research and
conservation efforts.
With best wishes for Good Birding,
Heather Gibbs (AWSG leg flag sightings)
[1] Danny Rogers, Hong-Yan Yang, Chris J. Hassell, Adrian N. Boyle, Ken G.
Rogers, Bing Chen, Zheng-Wang Zhang and Theunis Piersma 2010. Red Knots
(Calidris canutus piersmai and C. c. rogersi) depend on a small threatened
staging area in Bohai Bay, China. Emu 110: 307-315.
<http://www.publish.csiro.au/paper/MU10024.htm>
http://www.publish.csiro.au/paper/MU10024.htm
===============================
To unsubscribe from this mailing list,
send the message:
unsubscribe
(in the body of the message, with no Subject line)
to:
http://birding-aus.org
===============================
|
