Since 2004 there have been about 7 reported sightings of this species.
All, so far as I am aware, have been between Oct 1 and Oct 20. The two
at the Brattleboro Retreat Meadows were the 4th Oct and the 20th Oct
(though two years apart). This seems to signify a pretty narrow Fall
migration season and that this is definitely the time to be out there
looking for them.
Hector Galbraith PhD
Galbraith Environmental Sciences LLC
837 Camp Arden Rd., Dummerston, VT05301
802 258 4836 (phone)