Vydavatel US Fish and Wildlife Service, Department of the Interior
Datum vydání před více než 9 roky
US
beta
Shrnutí
Popis
These are raw data sheets with the results of a survey done at the Mason Neck National Wildlife Refuge Blue Heron Rookery in June of 1990. The volunteers counted the numbers of birds, nests and also identified the type of tree in which the herons nested.