192 
WATERFOWL BREEDING GROUND SURVEY IN NORTH DAKOTA 
Brandt V. Hjelle 
Introduction 
This report deals with the fifth annual State-wide migratory waterfowl survey 
carried out cooperatively by the Fish and Wildlife Service and the North Dakota 
Game and Fish Department, and also summarizes the waterfowl production studies 
carried on by the North Dakota Game and Fish Department in 1952. 
Methods of Sampling and Area Covered 
The annual State-wide migratory waterfowl survey was completed during the 
period May 6 - 20, 1952. 
This survey includes two phases: 
1, An aerial survey in which pilot-observer teams in light airplanes 
tally and geographically locate all ducks seen on 18 standardized 1/4-mile 
wide aerial transects crossing the entire State in an east-west direction. 
2. A ground survey by automobile in which observers count and identify 
all waterfowl seen within 1/8-mile on either side of the road on 8 ground 
transects crossing the State in a north-south direction. 
The 1952 aerial survey was made by pilot-observer teams furnished by the 
Game Management Division and Office of River Basin Studies of the Fish and Wildlife 
Service, and by the Pittman-Robertson Division of the North Dakota Game and Fish 
Department. The ground survey was made by personnel from the Pittman-Robertson 
Division. The pround and aerial surveys were conducted concurrently. 
Breeding Population Trends 
To obtain the most valid indices to State-wide populations, information 
reparding species composition and observed sex ratios obtained in the limited and 
selective ground counts, are applied to the mass population data obtained in the 
‘random and more complete aerial count. 
The first step is to correct for the factor of hens absent on the nest, or other- 
wise missed, during the survey. In this connection, all males seen during the 
ground survey are arbitrarily assumed to represent a breeding pair. On this basis, 
data from the 1952 ground survey as summarized in Table I1iI, indicated that observed 
duck populations must be increased by 35.1 percent to account for absent females. 
This "correction factor" is applied to the aerial data to obtain the corrected State-wide 
population index. 
Individual species indices are obtained by applying the observed species 
composition percentages obtained in the ground survey to the corrected State-wide 
population index. 
