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Bar-tailed Godwits need information 追蹤斑尾塍鷸
« on: Oct 12th, 2004, 9:39am » |
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For memeber's interest. Message extracted from Asia Pacific Migratory Watebird e-mail circulation:
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Greetings fellow shorebirders,
Bar-tailed Godwits are proving somewhat of an enigma in the Asia-Pacific region this year, and we are putting out a request for help!
Specifically, we would like to know (1) where the bulk of the Alaskan-staging godwits currently are, and when they got there, and (2) how many juveniles there are
at different sites along the Flyway in October and November.
In recent years there has been concern about the low proportion of juveniles seen in staging godwits in western Alaskan and after migration in New Zealand and Australia. This year, the picture in Alaska has become more complex. At two sites on the Yukon Delta, 'typical' low proportions of juveniles were recorded in early September. At another site, however,
juveniles outnumbered adults 6:1, and at least 700 juveniles were present.
This paints a very different picture of the apparent productivity of the Alaskan godwits. But we do not know whether this represents different site selection by adults and juveniles, or early departures of adults having left behind a large pool of young birds. Overall, comparatively small numbers of birds have been located in coastal Alaska this autumn, and some sites that
have held 10,000-30,000 birds in previous years held almost none. In New Zealand, arrivals in early-mid September did not seem to be especially large, so we are wondering if much of the population is still somewhere else that we do not know about.
So we are desperately keen to hear from anyone who has been out counting waders along the East Asian-Australasia Flyway where baueri godwits are found. If anyone has counts from August onwards, we would love to hear from you, even if it is to report that there are no godwits! We are particularly keen to hear from counters in Japan and eastern Australia.
We are also hopeful that we can encourage people to measure age ratios in their flocks. This is easily done with a telescope, and we have prepared some instructions on age identification and data collection that we can email to anyone who could help us with this.
It is likely that most of the godwits left in Alaska at the moment are juveniles that will soon start migrating south. In previous years, the first juveniles have been seen in Queensland (Australia) and New Zealand in
the 2nd week of October. As we write a large storm is brewing in the North Pacific that should be excellent for helping send godwits on their way.
Very little is known of the migration of young godwits, and while we assume that many migrate direct to Australia and New Zealand, we have nothing as
yet to prove this. Information on the ages of godwits through eastern Asia would help piece together a picture of how similar the migration patterns of
adults and juveniles are. And as an added incentive, there are five young godwits marked with prototype large numbered black flags on their right tibia. These were caught on the Yukon Delta in early September, and
we await the first sighting with interest!
Many thanks in advance for any help you can give, and we look forward to hearing from you!
Phil Battley (University of Otago, New Zealand)
Brian McCaffery (Yukon Delta National Wildlife Refuge, Alaska)
Bob Gill (US Geological Survey, Alaska)
___________________________________
Phil Battley
Department of Mathematics and Statistics
University of Otago
Postal address:
977 East Coast Rd
Kaiaua
RD3 Pokeno
New Zealand
HYPERLINK
"mailto:philbattley@quicksilver.net.nz"philbattley@quicksilver.net.nz
Phone 64 9 232 2603
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