Hi Tweeters,

Grant Hendrickson asks:

>We had always
>*assumed* that there was a resident population of Sanderlings with
>regular visitaitons by the other regular species.

I'd submit any 'resident' population of calidris genus shorebirds south of
northern Canada or Alaska this time of year are going to be first-summer
nonbreeding migrants that have not bothered going all the way to the north,
and are a miniscule part of the migratory population.

Here in Vancouver BC, where we have a pretty massive shorebird migration
(numbers about 1.5 to 2 million birds of 30-35 regular species, 50 in all
have shown up here) the northbound shorebird migration, not counting the
wintering Dunlin and Sanderling, peaks in late April and is done by the end
of May. There may be a handful of (usually) first-summer nonbreeders of
Black-bellied Plovers, Western and Least Sandpipers, Sanderling, sometimes
yellowlegs, which loiter here through the three-week hiatus between the end
of the northbound and the beginning of the southbound migration about June
22, when the first nonbreeding adult Westerns arrive here. Within a week
their numbers are in the thousands. Juvenile SemiSandpipers are the first
juv shorebird to arrive, about July 25, with Westerns a few days later.

>Is this complete lack of birds are typical phenomenon for this time of year?

If you're referring to shorebirds, and even more specifically calidris
shorebirds, the short answer is yes, though some of the nonbreeders may
'float' from site to site and others stay put through the three week hiatus.

>How long would such a condition be expected to last?

Until late June.

Michael Price
Vancouver BC Canada
michael_price at mindlink.bc.ca