Evaluation of Survey Methods for Colonial Waterbirds at Chase Lake National Wildlife Refuge, North Dakota, data release

We investigated methods to estimate the number of nests of waterbirds at a large, mixed-species colony at Chase Lake National Wildlife Refuge in south-central North Dakota in 2012 and 2013. The data were summarized and used in the analyses for a publication in a U.S. Geological Survey Open-File Report. The data consist of two data sets that were used to assess visible-nest counts for ciconiiform species conducted from the perimeter of nesting areas (hereafter perimeter counts) and observational surveys from fixed points outside the colony to count flights of adult ciconiiforms in and out of the colony (hereafter flightline surveys) as alternatives to within-colony counts of ciconiiform nests.