Date: 3/17/23 2:46 pm
From: Lance Benner <lbenner...>
Subject: Re: [LACoBirds] Swainson's Group 6
Migration counting at Bear Divide started on Thursday morning and the
totals are visible in eBird. Nobody saw Swainson's hawk there this
morning or yesterday morning. Note that those counts often end by 11
am, so if the big pulse of hawks seen in Altadena at 4 pm passed
through Bear Divide yesterday, there weren't any birders there to
observe them (I checked eBird: there weren't any reports in late
I received a couple of private emails from observers in Monrovia that
dedicated watches there this morning did not turn up any Swainson's
hawks, so apparently the lack of large flocks over Altadena was not a
fluke. It really looks like the birds either moved over the mountains
between Glendora and Monrovia, far enough south that observers in
Monrovia, Eaton Canyon, and Altadena were not able to see them, or
perhaps to high elevations where they would be very difficult to spot.
Part of our interest in extending a picket line to the north was to
understand the extent to which the hawks move through the San Gabriel
Mountains. On March 27, 2018 David Coates reported a flock of about
100 above the Chilao campgrounds. This year, most of the roads are
still closed due to snow and rockslides so we weren't able to place
any observers up there. Perhaps next year.
Weather could also play a role: today conditions have been very
different from yesterday, when there was a low overcast for most of
the day over the foothills. Swainson's hawks often fly below the
clouds and that can make them easier to see. On a day like today,
there weren't any low clouds in the morning so perhaps the birds were
flying higher.
On the general topic of weather, Luke and Kimball gently reminded me
to ask everyone who reports Swainson's hawks to note weather
conditions in their eBird lists: wind direction, speed if you can
(say, using the Beaufort Scale or mph), temperature, rain/drizzle,
percentage of cloud cover, and if clouds are present, the elevation of
the cloud bottoms. Yesterday, for example the clouds above Altadena
were down to about 3000-3200 feet around 4 pm, which I calibrated
against areas I could see where I've been hiking.
Thank you, and keep looking up!
Lance BennerAltadena

-----------------------------------------From: "Mike Peralez"
To: "Lance Benner"
Cc: "LACoBirds"
Sent: Friday March 17 2023 1:56:33PM
Subject: Re: [LACoBirds] Swainson's Group 6

Y. Lee saw hawks moving heading north from Easton canyon area....??
This morning's Glendora hawks all moved W or WNW. None appeared to go
north up the San Gabriel Canyon.
Perhaps Bear Divide might prove interesting.
Mike Peralez Glendora, CA
On Fri, Mar 17, 2023, 11:42 AM Lance Benner wrote:
I've been watching quite a bit from northern Altadena in the hope of
seeing some of the hundreds of Swainson's hawks that Mike Peralez
reported earlier this morning over Glendora. I've seen only three!
Where did they go?
Perhaps they went over the mountains? Or farther south along 210 in
Pasadena, and beyond where I could see them?
Lance Benner Altadena

----------------------------------------- From: <fantic5978...>
To: <LACoBirds...>
Sent: Friday March 17 2023 11:04:22AM
Subject: Re: [LACoBirds] Swainson's Group 6

Again just now repeat. Riding over the ridge. Maybe Midwick etc. will
provide better view

Yonghee Lee


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