[CT Birds] rarity-friendly weather

Nick Bonomo nbonomo at gmail.com
Thu Nov 5 15:18:33 EST 2015

Hi all,

I made the following post on my blog and figured it was worth
mentioning here too:

"Here in southern New England (and the northeast as a whole) we are in
the midst of an unseasonably warm spell for early November. As is
generally the case, a southwest flow is to thank. This weather tends
to get birders thinking about rarities and reverse migrants at this
time of year. November is rarity month, after all.

As you can see on the map above, a couple low pressure systems and
associated cold fronts are currently draped across the center of the
continent. Ahead of these is a warm southwest flow, and behind is a
cool northwest wind. We've talked about this a bunch of times over the
years, but it is worth mentioning every time. This pattern *may* bring
some cool birds to our region. The idea is that birds may move with
the winds ahead of the front ("reverse migrants" that go north instead
of south like they should), then might also get pushed back south with
the winds behind the front. This is what happens with Cave
Swallows...they ride the warm southerly flow from the Texas region
(presumably) to the Great Lakes region, then are pushed towards the
east coast when the winds shift after frontal passage. It is a pattern
that has played itself out many times over the past decade especially
and is often quite predictable. The current setup is not a classic
slam-dunk (the winds are not that strong nor terribly prolonged, and
Cave Swallow doesn't peak until mid-late Nov), but I think it gives us
a better-than-average shot at Cave Swallow.

Other species to consider? Well, rarities with a southern/western
origin might be more likely to appear with this weather. For example,
Ash-throated Flycatcher is a classic early November arrival under
these conditions. I'm still waiting for my first CT Franklin's
Gull...so how about that? I am placing my order now. Thank you.

Also thanks to the warm weather, we should expect some nice late
records of neotropical migrants, whether just from lingering
individuals or reverse migrants.

Shifting gears from reverse migrants to plain ol' migrants and
irruptives from the north. Sunday morning should bring a strong
passerine flight, and this may include some winter finches. There is
reportedly a massive Common Redpoll flight underway along the St.
Lawrence River in Quebec, so we could see some vanguards of that
movement. The first few Bohemian Waxwings have been seen in New
England. Also, there is an early movement of Snowy Owls that appears
headed our way in some capacity, and the first week of November is
prime time for the first of the season to reach Connecticut (and

I'm also wondering where that Cadillac Mountain Swainson's Hawk from
last weekend is going to turn up next... It could still be to our
north with the less-than-ideal hawk migration conditions of this

Nick Bonomo
Wallingford, CT

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