TY  - RPRT
TI  - Population trends of North American sea ducks as revealed by the Christmas Bird Count
AU  - D.K. Niven
AU  - J.R. Sauer
AU  - G.S. Butcher
PY  - 2005
UR  - https://pubs.usgs.gov/publication/5211310
ID  - 5211310
ER  -