If you look at the ebird data they are year round in massachusetts. pretty regular on any open water even in winter and def easy to find given the current winter as of today.
On Tue, Dec 29, 2020 at 10:36 AM Regina Harrison <onebirdlife...> wrote:
> I saw one at Woburn's Horn Pond on December 26. We have some hardy herons > here! I wonder if they are year-round residents, or more northern birds > coming south. > > Regina Harrison > <onebirdlife...> > Woburn, MA > > On Tue, Dec 29, 2020 at 8:52 AM alice morgan <morgan.alice...> > wrote: > >> To my surprise, there are two Great Blue Herons on the marsh this morning >> in Dartmouth! >> >> -- >> Alice & Dane Morgan >> Brookline & S. Dartmouth, MA >> > -- Justin Lawson