CAPE MAY POINT, New Jersey—Two years ago migrating monarch butterflies transformed the lush gardens of Cape May Point into a series of "giant orange snowglobes." That's how Mark Garland of the Monarch Monitoring Project describes the good monarch days, the kind of days when thousands fly overhead.

There's been no such spectacle yet this year, but Garland and members of the project's team, who take a census of the monarchs three times a day, are holding out hope. The popular orange-and-black insects will be drifting toward this peninsula for a few more weeks to fill up on nectar before riding the winds that will hoist them over the Delaware Bay and on toward Mexico.

Holding one gently in his fingers, Garland