Bill Bousman

Dear Sylvia and EBB,

Just to add my two cents. The "Birds of Northern
California" is an amazing resource and has more
than stood the tests of time since its
publication. Just to emphasize what Joe said,
the Swainson's Thrush bar graphs on p. 58 shows
this thrush in two roles. The first is its role
as a breeding summer resident in the wet coastal
forests and mountains of northern California and
the second is as a passage migrant both through
areas where they breed and areas where they do
not. If you live on the wet bayside coast of
Alameda or Contra Costa counties where these
birds breed, then the first bar graph is your
best guide, otherwise, the second bar graph will show you when to expect them.

For what it's worth, at the Coyote Creek Riparian
Station near Milpitas, we banded 2458 Swainson's
during the spring passage from 1986-1996 and 1996
Swainson's during the fall passage for those same
years. This is a location where this thrush has
not nested in a hundred years, so these are all
passage birds. For the fall passage the 5th
percentile date for these records was 3 Sep and
the 95th percentile date was 13 Oct (that is, 90%
of all birds came through between 3 Sep and 13 Oct).

Bill Bousman
Menlo Park

At 09:23 PM 9/1/2016, Joseph Morlan [EBB_Sightings] wrote:


Golden Gate Audubon hosts a digital version of "Birds of Northern
California" which has useful bar-graphs showing expected arrival and
departure dates.

The graph on page 58 shows Swainson's Thrush to be common through early
September becoming uncommon through the end of the month and rare through

This chart....

indicates the species departs Marin County in mid-October.

On Thu, 1 Sep 2016 19:30:52 -0700, "Sylvia Sykora
[EBB_Sightings]" <> wrote:

How late do Swainson's Thrush remain here in
autumn? I've had one coming to the water,
morning and evening, all week, latest today, Thursday, September 1.

Sylvia Sykora
nr. Skyline and Castle
Joseph Morlan, Pacifica, CA

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