(from the China Data Center)

This birds data is contributed by Diana Stralberg, School of Natural Resources
and Environment. The dataset includes five layers: landscape data (landuse),
the presence/absence data for each species, and the abundance data for each
species.

LANDUSE - an area of south California. It includes the following variables:
DISTANCE - distance to nearest urban edge;
URB1000 - urbanization proportion within 1000m radius;
URB250 - urbanization proportion within 250m radius;
EDGE1000 - amount of urban edge within 1000m radius (an index of fragmentation)

PRESS100 -singing males only.
PREST100 - all birds. 
These two files contain variables indicating the numbers of total species
(RICH1, RICH2), migratory species (MIG1, MIG2), chaparral species (CHAP1,
CHAP2), and urban species (URB1, URB2).

SING100 - singing males. 
TOT100 - total individuals.
These two files contain abundance data for each species, as well as the urban,
migratory, and chaparral species summaries.