Hi all
As an impartial observer, I have been avoiding this
debate too. Because of recent postings however, some
points of issue need clarification.
Lets examine why multiple leg flags on a small bird
may be detrimental to it.
Leg flags are in fact uncontrolled rudders with no
bearings. On a small bird such as a Red-necked Stint,
the leg flags have a combined surface area greater
than 15% of the total surface of the bird. This is
most significant. Now I don't claim to be an impartial
aeronautical engineer however one does not need to be
an intellectual giant to assume that combined with
their additional weight, attaching numerous large
uncontrolled rudders to a small flying object would
have a radical influence on it's control, particularly
in strong winds.
On a small bird such as a Red-necked Stint, Curlew
Sandpiper or Little Tern, during calm conditions while
roosting on a level surface, the flags may have little
impact but as the wind increases to strong and
gusting, the birds would be buffeted severely by the
wind sail effect from their leg flags. This would be
much worse if the birds are on an irregular snag
covered surface that induces turbulence. Some
observers have noted that leg flagged Stints are
tumbled about uncontrollably when they attempt to move
over sea weed in winds of 20+ knots and that the flags
were prone to tangling from fine strands of weed.
In extreme conditions, the influence of leg flags are
likely to be catastrophic to the bird, caused from the
interaction of wind on these uncontrolled rudders as
the bird attempts to alight, scramble or roost and
generally maneuver to cover. Obvious? Before my
critics say that I have no proof that this happens, I
say there is a growing amount of evidence to show that
leg flags are detrimental to small birds in strong
winds, convince us that they are not!
Correlation? Is there a correlation between leg flags
and the reported deaths of many Little Terns at Lake
Tyers on Christmas eve? More than 20% of the dead
Terns were banded and many more flagged birds are not
unaccounted for! So the result speaks for itself.
Where are they now?
I have heard of a Curlew Sandpiper that was retrapped
eighteen years after it was ringed with a single metal
band (not multiple flagged). So we know these small
waders can live for many years. Apparently many
thousands of Red-necked Stints have been multiple
flagged and banded within Australia in the last few
years so its reasonable to assume with such proven
longevity, that if the flags don't harm the birds,
that most of them should still be alive today.
Where are all these multiple leg flagged Red-necked
Stints now? An obvious correlation is that the leg
flagged Stints are missing. Do they have a much
shortened life span due to their leg flags? Should the
missing birds be presumed dead?
How about one of the "pro banders" posting on
birding-aus, the following information about
banded/leg flagged Red-necked stints; The date,
precise number and location of where these birds were
marked and the colour band/flag id of all birds marked
since July 1997. This will enable all of us to
appreciate the extent of the Stint flagging project
over the last five seasons, and perhaps encourage some
of us to go looking for the survivors.
Obvious? --- Questions need to be asked about where
are all the missing leg flagged waders. Why are they
missing?
Obvious? --- There are none so blind as those who
cannot see!
Cheers
Kym Bennet
Carnegie Victoria
http://my.yahoo.com.au - My Yahoo!
- It's My Yahoo! Get your own!
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