The Breeding Bird Survey, begun in 1966, now consists of approximately 3,000 randomly selected routes throughout the United States and Canada of which approximatsely 2000 are run each breeding season. It is roadside survey starting 112 hour before sunrise that uses a standardized technique consisting of recording all birds heard or seen in three minutes at 50 stops, each 1/2 mile apart. The survey is described in Robbins, C.S., D. Bystrak and P.H. Geissler, The Breeding Bird Survey: Its First Fifteen Years, 1965-1979, USF&W Resource Publ. 157 (1986).