Robert and Oregon Birders,
I was also interested in the comments about a “poor” shorebird migration.
Here where I live in the Vancouver, BC area, we have never experienced a “poor”
shorebird migration. Huge numbers congregate every year around the Fraser River
estuary (including Boundary Bay), and the numbers and timing seem very
consistent from year to year, peaking for most species between April 20 and May
10. The most abundant species are Western Sandpiper, Dunlin, Least Sandpiper,
Black-bellied Plover, Short-billed Dowitcher, and Whimbrel.
The problem, as I see it, is that coastal Oregon does not have any major
shorebird staging areas (“major”, in my minding, meaning capable of supporting
50,000 shorebirds at once). Many migratory birds, including waterfowl and
shorebirds, proceed in spring by a series of hops between staging areas, which
provide lots of food and where they may stay for several days before proceeding
to the next staging area.
Major staging areas on the Pacific coast include San Francisco Bay and Humboldt
Bay in California, Willapa Bay and Grays Harbor in Washington, the Fraser
estuary and probably the Tofino flats on Vancouver Island in BC, and the Copper
River delta in Alaska. There are none that I would consider “major” in Oregon,
although there are numerous minor and even medium-sized estuaries.
So I’m sure that the answer to your question is simply that most shorebirds
overfly Oregon, flying non-stop from California to Washington or BC. The
numbers that stop in Oregon probably vary a lot from year to year depending on
weather; if they encounter adverse weather, more of them may stop in Oregon,
but only as long as needed till they continue farther north.
The exact pattern of migration differs from species to species. Species such as
Red Knot and Short-billed Dowitcher make a particular point of skipping Oregon.
The “highest counts” on eBird tell part of the story, although average counts
would be more meaningful. For Red Knot, the all-time high count for WA is 4000
birds; for Oregon, 55. It is easy to see hundreds of these birds in mid- to
late May on Willapa Bay or Grays Harbor. For Short-billed Dowitcher, the
all-time high for WA is 25,000; for OR, 1700.
Shorebirds are very strong fliers, and in many cases, if well-fed before they
leave, can fly many hundreds or even thousands of miles without stopping.
Classic cases include Pacific Golden-Plovers and Bristle-thighed Curlews which
cross thousands of miles of ocean to winter on Pacific islands.
If any readers who are experts on shorebird migration would like to respond
with further details, I would love to hear them, but I believe the general
pattern that I’ve outlined is reasonably accurate.
And by the way— I count myself lucky to be among those who saw the 2
Bristle-thighed Curlews at Fort Stevens State Park in 1998.
Having heard about them on OBOL, I changed my planned destination for a weekend
in late May, and was rewarded with great, close-up views of these birds. They
are still the only Bristle-thighed Curlews I’ve ever seen!
Wayne C. Weber
Delta, BC, Canada
contopus@xxxxxxxxx
From: obol-bounce@xxxxxxxxxxxxx [mailto:obol-bounce@xxxxxxxxxxxxx] On Behalf Of ;
Robert O'Brien
Sent: Saturday, May 16, 2020 10:34 AM
To: obol
Subject: [obol] Re: Coastal Spring Shorebird Migration Questions
There have been quite a few comments about a 'poor' shorebird migration on the
Oregon coast this spring.
So, my question is that, since they are surely migrating, do we get few in some
years because of some combination of the following
1. They overfly Oregon, and
2. They migrate at night and are not seen in flight?
3. They migrate at an altitude too high to be seen during the day?
4. They fly farther offshore (added by Jim Danzenbaker)
5. Or?
And I guess the same questions could apply to fall migration as well.
On Sat, May 16, 2020 at 9:53 AM Robert O'Brien <baro@xxxxxxx> wrote:
There have been quite a few comments about a 'poor' shorebird migration on the
Oregon coast this spring.
So, my question is that, since they are surely migrating, do we get few in some
years because of some combination of the following
1. They overfly Oregon, and
2. They migrate at night and are not seen in flight?
3. They migrate at an altitude too high to be seen during the day?
4. Or?
And I guess the same questions could apply to fall migration as well.
Bob OBrien Carver OR
