Five-minute grid of marine bird biomass density surveyed off central California - Upwelling season, 1980-2001 (CDAS data set Up0_mass.shp)

Up0_mass is a polygon shapefile representing 5 minute x 5 minute latitude x longitude cells that house the overall total biomass densities (kg/sq km) of 76 species of marine birds in the Upwelling season (March 15 - August 14, 1980-2001). Density for each of 76 marine bird species was multiplied by average body mass for that species, and these products summed for all species in a cell, to obtain total biomass density. Cells that were surveyed but in which no birds were observed have total biomass densities of zero.