May is also a great time for birding on Long Island. The trees are green but not so dense as to interfere with the shots. Birds are also very active and bright for mating season. All you have to do is follow the calls.
I spent Saturday at Robert Mosses State Park, right near where they were filming Men In Black 3. The massive tents for MIB3 are still standing but no activity. I did bring my camera, just in case. At least it was a beautiful day.