Until recently, few people tracked southern New Jersey's butterflies with the same vigilance paid to its migratory birds.
But Jack Connor, a butterfly hobbyist from Port Republic and a writing professor at the Richard Stockton College of New Jersey, decided in 2008 to launch an Internet butterfly database and encouraged friends and acquaintances to report their sightings.
Last year, he had 50 observers who posted 8,000 sightings.
Already this spring, he has had 2,000 observations of butterflies with names such as hackberry emperor and red-spotted purple.
New Jersey is home to just 100 native species and about 60 more occasional vagrants.