P. sennae (Cloudless Sulphur) outbreak in record proportions

[Pavulaan at aol.com]

Yesterday, Sept. 2, I visited Williamsburg, VA. and was amazed at the numbers
of P. senna everywhere.  This outbreak is definitely the largest I have seen
in the east, thought the midwestern outbreak of 1987 was considerably heavier
in Missouri and Illinois.  The butterflies could always be seen, with several
in view at all times, everywhere.  

Adult sennae were especially attracted to a bed of giant Hibiscus (Rose
Mallow) flowers, where they were SWARMING, preferring only the red blossoms.
Virtually all flowers were occupied by these butterflies, which competed with
each other to enter the flowers first, and only one at a time.  Once an adult
entered a flower at a time, while the others would back off until that adult
left, then it was a free-for all, all over again (a butterfly version of
musical chairs: musical flowers).  Due to the limited number of blooms, dozens
had to wait their turns, so they kept flying all about.  As usual, no camera.

Anyone up north see similar behavior?  Has anyone north of Boston seen them
yet?

Harry Pavulaan