[CT Birds] Bluff Point expectations for Monday Tuesday

David Provencher davidprovencher at sbcglobal.net
Sun Sep 9 10:40:17 EDT 2012

I still expect Monday and Tuesday to be good days at Bluff Point in Groton.
I expect Tuesday to offer better views of the birds undergoing morning
flight however. Briefly here is why:


I have learned from years of experience that breezy mornings cause the birds
to leave the trees of the reserve earlier, which often results in many birds
flying very high over the area birders use to observe the event.
Additionally, the trees are moving in the breeze which makes finding those
birds moving through the vegetation more difficult to find and see well.
These can be frustrating days, when thousands of birds pass overhead with
just a small number being seen decently (or at all). My theory for why birds
head higher sooner on breezy days is that birds prefer to fly in stable air
(flight efficiency, energy usage, etc.), and the most unstable air on a
breezy day is going to be at the interface of the forest canopy with the
moving air, where the breeze tumbles and swirls as it interacts with the
trees and other obstacles (like waves breaking on a beach). So I believe the
birds rise up quickly on these breezy mornings to get out of this turbulent
air into the steadier flow above.


Monday's forecast is for a breezier day than Tuesday, and it is most
definitely my experience that the second clear night after a strong Fall
cold front is far more stable than the first night (has to do with high and
low atmospheric differential pressure, blah blah blah). So I have often
experienced a better morning of birding at Bluff on the second morning after
the front, even though more birds often move on the first night. So my
expectations is for a good push of migrants tonight and a good (but smaller)
push tomorrow night. My bottom line guess is this; more birds Monday
morning, better views Tuesday morning.  Fingers crossed.


Dave Provencher

Naturally New England


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