TY  - RPRT
TI  - Detection ratios on winter surveys of Rocky Mountain Trumpeter Swans Cygnus buccinator
AU  - J. Bart
AU  - C.D. Mitchell
AU  - M.N. Fisher
AU  - J.A. Dubovsky
PY  - 2007
UR  - https://pubs.usgs.gov/publication/70031368
ID  - 70031368
ER  -