They can be far north in Champlain Valley and up the CT river valley
bottom. They seem to be moving farther and farther north over the years
as are a number of other bird species.
In fact, you can look at the species on Vermont eBird and see that there
is even a record in the Northeast Kingdom now! Click here
to go to Mockingbird report on Vermont eBird. If you change the location
there to all of North America, you can see that there are records up
into Quebec too. And you can visit Vermont eBird at www.ebird.org/vins
and enter you sightings too. Also, check out the reports on them from
the Vermont Breeding Bird Atlas database - http://www.uvm.edu/~vbba/.
Conservation Biology Department
Vermont Institute of Natural Science
27023 Church Hill Rd.
Woodstock, VT 05091
Visit the CBD Blog: http://www.vinsweb.org/cbd/news.html