Search Results
1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, and 1998. Patuxent Wildlife Research Center. This line shapefile portrays the current routes used for conducting Breeding Bird Surveys in the lower 48 States. This layer is part of the 1997-20... National Atlas of the United States.