The Ehrenberg pigeon trap, a portable unit which utilizes a pigeon as bait for collecting mosquitoes, was utilized as a vector surveillance tool during the 1975 outbreak of St. Louis encephalitis in New Jersey. The trap was highly selective for Culex species and the majority were Culex pipiens. Ovarian dissections using the Detinova technique revealed that the trap collected parous and nulliparous C. pipiens in nearly equal numbers. The utility of the trap as well as its selectivity for C. pipiens of broad physiological age make this trap an efficient tool for St. Louis encephalitis vector and virus surveillance.