As far as distinguishing robin-sized birds from ducks or even geese we
should take into account that the signal varies as the 6th power of the
size of the bird. As Cliff Mass says a bird will give a much larger signal
than a raindrop. So will a goose a much larger signal than a robin. I don't
really know how to interpret the signals shown on these radar maps but I'm
sure some people do. Bob O'Brien Portland
On Saturday, March 7, 2020, Robert O'Brien <
baro at pdx.edu> wrote:
>
I believe Robins could be the answer. I live in a rural area south east of
>
Portland and there has been a real uptake in Robins within the last month.
>
And this is not unusual, it happens most Winters here.
>
And being accompanied by Varied Thrushes is an additional possibility.
>
I grew up on the San Francisco peninsula and Robin's frequently flew over
>
at altitudes of several hundred feet in flocks of 10 to maybe 50. In some
>
Winters they were indeed joined by varied thrushes. These are easily
>
detected among the robins because they show a faint white wing stripe
>
underneath. This was in the daytime of course because they wouldn't be
>
visible to the human eye at night.
>
>
Bob O'Brien Portland
>
>
On Friday, March 6, 2020, B Boekelheide <bboek at olympus.net> wrote:
>
>>
Hello, Tweeters, et al,
>>
>>
What about robins? Even though many robins stay in WA through the
>>
winter, many more begin to pass through around this time, particularly
>>
brightly-colored males on their way north that probably spent the winter in
>>
CA and OR. The early bird catches the territory, you know. On the
>>
Wednesday morning bird walks in RR Bridge Park near Sequim, there is a
>>
distinct increase in robins in late winter, like in February and March. In
>>
the last week around here we have noticed more robins on territories and
>>
more robins singing in the morning.
>>
>>
And we all know there are a lot of robins out there.
>>
>>
Just a guess.
>>
>>
Bob Boekelheide
>>
Dungeness
>>
>>
*Subject: Bird Migration on Radar*
>>
Date: Fri Mar 6 2020 18:05 pm
>>
From: jdanzenbaker AT gmail.com
>>
>>
>>
Hi Tweeters and Dennis,
>>
>>
I'm just reading this thread with interest. To answer the question from
>>
>>
Dennis, nope, didn't notice any appreciable increase in any species or
>>
>>
family of birds down here in Clark County yesterday. However, three other
>>
>>
Clark County birders and I were birding in Skamania County all day! This
>>
>>
morning, I visited the Vancouver Lowlands and witnessed about 15,000 geese
>>
>>
(Snow and Cackling) feeding in the corn fields. However, these are
>>
>>
(probably) birds that winter here so they wouldn't have triggered a
>>
>>
migration alert since I think most only commute between Suave Island,
>>
>>
Oregon and the Vancouver lowlands - about 3 miles as the goose flies.
>>
>>
There were also about 600 Sandhill Cranes but they are diurnal fliers. The
>>
>>
number of cranes may have increased in the last several days - but maybe
>>
>>
not since I'm not there every day to count them. Also, as Dennis stated,
>>
>>
most (if not all) goose and crane commute time is during daylight hours.
>>
>>
True goose migration is nocturnal. I don't think there was any nocturnal
>>
>>
goose migration going on since there were no reports on OBOL of goose
>>
>>
flocks heard overhead at night. Good numbers of swallows started arriving
>>
>>
several weeks ago but its impossible to know what the daily turnover is
>>
>>
with Tree and Violet-green Swallows.
>>
>>
>>
Seems like there was an uptick in sparrows this morning - Savannah Sparrows
>>
>>
have arrived and blackbird flocks were more numerous. However, blackbirds
>>
>>
have nocturnal roosts even during migration - I think.
>>
>>
>>
Keep your eyes and ears skyward and on those migration computer screens!
>>
>>
>>
Jim
>>
>>
Battle Ground, WA
>>
>>
>>
> Hi Andy and tweeters,
>>
>>
> Very interesting to read Cliff Mass�s blog. But I expressed puzzlement a
>>
>>
> while back when a spectacular radar signal was shown in the Florida Keys in
>>
>>
> late February that people attributed to bird migration. When I lived in
>>
>>
> Miami for 15 years, the only incoming migrants in late February were Purple
>>
>>
> Martins and Swallow-tailed Kites, both of which are diurnal migrants and in
>>
>>
> any case wouldn�t give a radar signal like that.
>>
>>
> I�ll ask the same question here. The only migrants that normally come into
>>
>>
> this area in early March are swallows and a few Rufous Hummingbirds, which
>>
>>
> are diurnal migrants. I would expect no movements other than that. Thus I�m
>>
>>
> still not entirely convinced, unless someone can point out something I have
>>
>>
> missed. Possibly waterfowl? But of course they also do a lot of their
>>
>>
> migration in the daytime and would not start at dusk and stop at dawn.
>>
>>
>>
> Jim Danzenbaker, you�re looking at the sky. Any massive arrivals in your
>>
>>
> area yesterday?
>>
>>
> And what could it be if not birds?
>>
>>
>>
> Dennis Paulson
>>
>>
> Seattle
>>
>>
>>
> Date: Fri, 6 Mar 2020 08:13:19 -0800
>>
>>
> From: "Andy Stepniewski"
>>
>>
> To: "TWEETERS"
>>
>>
>
>>
> Tweeters,
>>
>>
> Cliff Mass in his 6 March 2020 weather blog documents substantial numbers
>>
>>
> of birds migrating north from Portland OR on Wednesday night (4 March).
>>
>>
> Further, he explains the weather pattern that night was conducive for
>>
>>
> migration, giving the ?birdies? as he calls them, a tailwind.
>>
>>
>>
> See ?Weather Radar Shows Spring Bird Migration:?
>>
>>
> https://cliffmass.blogspot.com... <https://cliffmass.blogspot.com/2020/03/weather-radar-shows-spring-bird.html>
>>
>>
>>
> Pretty cool stuff!
>>
>>
>>
> Andy Stepniewski
>>
>>
> Yakima WA
>>
>>
> steppie at nwinfo.net
>>
>>
>>
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