Not sure what size birds were seen, but American Crows are a likely candidate. Every evening in the winter, flocks gather from all around the area to roost communally. Many years there is a large roost in Lebanon with upwards of three thousand birds. Streams can be seen headed in that direction starting by early afternoon and can become quite a sight.

Spencer 
Norwich


On Jan 5, 2012, at 5:50 PM, Alexander Dickey <[log in to unmask]> wrote:

> Wow, sounds like quite a sight! The only thing I can think of is European
> Starlings. I've seen them performing similar aerial shows in film clips
> from Europe. At times they fly together in beautiful shape-shifting
> "clouds." I've seen them do it here as well, but never as spectacularly as
> in the videos of them from their native continent. You might try looking
> their flocking behavior up on Youtube. Good luck!
> 
> Best,
> Alex Dickey
> 
> On Thu, Jan 5, 2012 at 3:31 PM, Anna Slack <[log in to unmask]> wrote:
> 
>> Hello Birders!
>> 
>> As I was headed home on I-89 last night I noticed very large flocks of
>> birds - or possibly one huge flock - trailing in a huge ribbon across the
>> sky between the Dartmouth exit and heading on back toward the construction
>> mess in West Lebanon.  Not being trained in such things I was curious to
>> see if it would make mention on the listserv today - did anyone else
>> experience this?  What were they?  It was quite impressive, it reminded me
>> how entire caves of bats will fly in mass exodus into the night skies for
>> feeding.  So much so, in fact, that I began to wonder if it was bats....or
>> what could have possibly stirred up such a movement.
>> 
>> Thanks for any info & please forgive if my terminology is not correct!
>> 
>> Curiously,
>> 
>> Anna Slack
>> 
>> Programs Coordinator, UVLT
>>