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See this recent news on the World Waders site, for a start.
Then, news from the International Wader Study Group is posted here.
If you're REALLY into shorebirds, become part of the IWSG listserv, by going here.
And, eBird has a page devoted to the International Shorebird Survey - see it here.
Although it is a little dated, this publication from USGS shows info on North American shorebird populations.
(image of knots from National Digital Library - Greg Breese)