Wow. Very informative & helpful. So, David, do you think it would work
to try the 'night' recording gimmick in the cited webpage and then ID
various species by sonograms? Perhaps even get a 'count' that way;
calls/minute? Have you detected mixed flocks? Various size flocks? Ever
heard of censusing Swainson's thrushes that way? That is quantitatively
all night rather than by just counting them audibly for a short time
period? Now I know that people often report audible Swainson's counts per
time period on OBOL, but potentially this could run all night and get
useful information comparable from year to year?
But, can yone really record a multihour sonogram and then.digitize it as
the web page implies? If so, it could easily be played back on a computer
screen.
Were there high pressure conditions when you 'saw' or 'heard' them? Might
they fly lower during windy conditions? And undetectably high during still
or favorable wind conditions? At what altitude have you seen the
migrations? For instance the Knots? What were the wind conditions then,
if you or Tom recall.
All the pelagic trips I led, mostly out of Tillamook, a few out of Ilwaco,
I only recall one migrant flock, a nearshore flock of 20-30 (likely) Common
Terns at low elevation closer to shore than the boat. The only BC to LA
cruise I took had many flocks of Sabine's Gulls. So I'm really talking
about shorebirds here, not seabirds.
Bob OBrien
On Tue, May 19, 2020 at 1:46 PM David Bailey <davidcbaileyoregon@xxxxxxxxx>
wrote:
*detections* not defections
*netting* not meeting
Autocorrect typos, sorry...
On Tue, May 19, 2020, 13:43 David Bailey <davidcbaileyoregon@xxxxxxxxx>
wrote:
My observations of shorebird migration in Oregon:
Q. Do shorebirds migrate during the day?
A. Yes--in Spring under the right conditions I have observed flock after
flock moving north along the shore or just offshore, and even out on a
pelagic trip once in April (Red Knots, Tom Love may recall). Whimbrel are a
very obvious spring migrant during the day as they move in flocks of
hundreds and are constantly calling. I don't recall hearing them migrating
much at night like I have Calidrids and phalaropes.
Q. Do shorebirds migrate during the night?
A. Yes--I often go out at night to listen for nocturnal migrants and many
times hear calling shorebirds migrating overhead since living on the coast.
I would say that I have detected shorebird migrants much more
consistently during nocturnal surveys (informal) than diurnal observations
by sight. This parallels defections of southbound migrant Swainson's
Thrushes in late summer where it's easy to count hundreds passing overhead
at night, but during the day their migration is nearly undetected unless at
a meeting and banding operation such as what Mike Patterson has directed
here in the past.
David C. Bailey
Seaside, Oregon
On Tue, May 19, 2020, 11:32 Robert O'Brien <baro@xxxxxxx> wrote:
A very interesting discussion. So far.
Now, if they are flying over/past Oregon, do they do it by night, day,
or both.
Do the few that land show up overnight, in the morning, the afternoon,
or ? Roy has addressed this to an extent recently.
A few years back I encountered about 1000 Western Sandpipers at the
'ponds'
at the South Jetty of the Columbia. This was in mid-late summer. They
were feeding in the ponds but flying around pretty often,
and did not seem to be 'stocking up'. Rather just likely taken down by
the intermittent stormy weather.
As evening got darker they started heading off south, but not in a
group, rather flocks of 10-50.
In contrast, when they flew around at the ponds they did it in very
large masses.
Leaving very late in the day could imply that they were waiting for
nightfall, as do passerines. The weather was still quite unsettled.
Passerines, of course, wait til 30-6 minutes after sunset when it is
quite dark.
Of course on a long flight they might not be able to make it entirely by
either day or night and could overlap.
But in general there are the questions:
At what altitude do they fly? Day, Night, Both? Offshore? How far?
Are they calling?
I don't recall a pelagic trip ever reporting large shorebird flocks
overhead, but maybe they are too high?
Here is an idea to explore these questions for the many OBOL
'Soundbirders'
Seems easy enough to implement? But of course, one might come up with
'nothing'.
Other than the sound of the waves................
http://soundbirding.org/index.php/2017/07/18/night-migration-shorebirds-at-the-window/
Bob OBrien Carver OR
