[CT Birds] CT shorebird numbers

Greg Hanisek ghanisek at rep-am.com
Sat Aug 21 16:38:19 EDT 2010


I'm with you Nick. The first time this really struck me was more than 30 
years ago in NJ. A reservoir I frequented (Spruce Run Reservoir in Hunterdon 
County) was drawn down during southbound migration, and during a prolonged 
period of rainy, humid, socked-in weather we enjoyed the best inland 
shorebirding I've ever encountered. In addition to a long list of shorebirds 
and herons, which built up species and numberwise during this weather 
episode, we even eventually got a Black Skimmer more than 50 miles from the 
coast.

But when a cold front finally arrived, virtually everything left overnight.

Greg Hanisek
Waterbury

----- Original Message ----- 
From: "Nick Bonomo" <nbonomo at gmail.com>
To: "CTBirds" <ctbirds at lists.ctbirding.org>
Sent: Saturday, August 21, 2010 2:14 PM
Subject: [CT Birds] CT shorebird numbers


> Larry Flynn just emailed me to mention that the shorebird numbers
> around the Norwalk Islands were much reduced this morning as compared
> to previous days. It got me thinking about shorebird movements in CT.
>
> Generally speaking, we think of cold fronts and the northerly winds
> behind them as mechanisms to concentrate passerines and hawks at
> migration hotspots during autumn. In Connecticut, shorebird numbers
> seem to work differently. I and others have observed that shorebird
> numbers often build to a peak during conditions not conducive to
> migration (i.e. hot and humid weather with a breeze from the south or
> east). Then, a strong cold front will clear out these concentrations.
> The cycle will repeat: numbers build, then the next cold front sweeps
> them away.
>
> Why? Perhaps during ideal migration conditions, birds moving North to
> South easily bypass our East-West coastline and continue their
> migration to Long Island and beyond. Shorebirds just do not seem to
> pile up against our coastline. Maybe the brief water crossing (Long
> Island Sound) does not act as much of a barrier for the strong-flying
> shorebirds, while hawks and passerines try to avoid crossing water
> when possible. That seems to make sense, but who knows for sure. While
> fishing mid-sound I often see flocks of shorebirds crossing the sound,
> while the hawks and passerines usually move east-to-west down the
> coast instead of crossing.
>
> And why do numbers increase during poor migration conditions? Maybe
> newly-arrived migrants are spread all along the coast when they first
> arrive on the heels of a cold front, then gradually locate and remain
> at the best habitat over the next few days until they ride the next
> period of north winds to points south. That would account for a
> gradual build-up over several days. It should also be noted that
> shorebirds are more likely to migrate during less-than-ideal
> conditions (than, say, hawks or songbirds) because they are such
> strong flyers.
>
> Larry's observations may reflect those of folks who are shorebirding
> along the CT coast today, because yesterday evening's conditions were
> fine for migration. A large number of shorebirds may have departed. Or
> not...these are just general observations and by no means a rule.
> Also, this applies to numbers but not necessary diversity, which is
> more dependent on the calendar date. For instance, we are now entering
> the period of highest shorebird diversity in CT, thanks to the arrival
> of "grasspipers" such as American Golden-Plover, Baird's Sandpiper,
> and Buff-breasted Sandpiper.
>
> For those wondering if a reduction of shorebird numbers could put a
> damper on tomorrow's Shorebird Workshop, I wouldn't be too worried.
> These things vary from day-to-day and location-to-location. Even if
> shorebird numbers were reduced by the recent north breeze, tomorrow's
> forecast is for cloudy skies leading to inclement afternoon
> weather...perhaps the best shorebirding conditions CT has to offer! If
> you're shorebirding tomorrow, don't let the rain chase you home. In
> addition to the typical habitat, coastal lawns (Hammo or Sikorsky
> Airport) or inland fields and pond edges (Rocky Hill Meadows) can be
> superb during and immediately after rain.
>
> Nick Bonomo
> Wallingford, CT
> http://shorebirder.blogspot.com/
>
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