Closeup of Eastern Poison Ivy Toxicodendron radicans, shot at the Jamaica Bay Wildlife Refuge in Queens, New York City. This special place is part of the Jamaica Bay Unit of Gateway National Recreation Area.

The active compound in the plant's sap that causes the often virulent skin reaction, including rash and blistering is called urushiol. But many birds and other animals eat the plant and its seeds with no ill effect.

Learn more about Gateway National Recreation Area by visiting www.nps.gov/gate.