Tim -
At 09:12 PM 20/11/02 +0800, you wrote:
>I await accurate statistics.
There are plenty of data around for statistical analysis. There are yearly
stats (going back way before leg-flagging began) on proportions of
juveniles in Curlew Sandpiper (and other wader) populations, which indicate
breeding success for those years, and can be used in conjunction with other
data to derive information on survival rates (which also vary from year to
year). This kind of information is published regularly in The Stilt.
Darryl has also pointed to what is easily accessible on the AWSG website,
and which makes instant nonsense of some of the unsubstantiated claims we
have seen thrown around. So it would quite possible for someone to put in
some time and effort to look into the conjectural mortality caused by
leg-flagging.
A proportion of Curlew Sandpipers (whether flagged or not) dies each year,
and new, young, birds enter the population each year. With the known
figures on flagged numbers, it seems unlikely that the proportion of the
population that is flagged would be more than about one or two percent at
most (and unlikely to increase without a large and ongoing increase in
banding effort). The whole 'mystery' of the supposedly missing birds
disappears - one of those strange conspiracy theories or urban legends that
get repeated again and again without a shred of substantiation (or even
logical thought) behind them.
Time to move on...
Cheers,
Hugo
Hugo Phillipps
Communications Coordinator
Birds Australia
415 Riversdale Road
Hawthorn East 3123, Australia
Tel: (03) 9882 2622, fax: (03) 9882 2677
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