TY  - RPRT
TI  - An evaluation of the Christmas Bird Count for monitoring population trends of selected species
AU  - G.S. Butcher
AU  - M.R. Fuller
AU  - L.S. McAllister
AU  - P.H. Geissler
PY  - 1990
UR  - https://pubs.usgs.gov/publication/5222405
ID  - 5222405
ER  -