Mid winter population size indices for dabbling ducks

Mid-winter population size indices for dabbling ducks in Suisun Marsh during 1953 to 2009. Solid line illustrates the population trend and was estimated with a LOESS function. Mid-winter waterfowl data were collected by the California Department of Fish and Game and U.S. Fish and Wildlife Service. Suisun Marsh was not surveyed as part of the mid-winter waterfowl survey in 2010 and 2011. 

Figure from Ackerman, JT, MP Herzog, GS Yarris, ML Casazza, E Burns, and JM Eadie. 2014. Chapter 5: Waterfowl ecology and management. Pages 103-132 and maps 10 and 11 in Moyle, PB, A Manfree, and PL Fiedler (editors): Suisun Marsh: Ecological History and Possible Futures. University of California Press: Berkeley, California. 239 pages.