TY  - RPRT
TI  - Behaviour patterns of Mallard Anas Platyrhynchos pairs and broods in Minnesota and North Dakota
AU  - P.J. Pietz
AU  - D. A. Buhl
PY  - 1999
UR  - https://pubs.usgs.gov/publication/70021601
ID  - 70021601
ER  -