176 
WATERFOWL BREEDING GROUND SURVEY IN COLORADO, 1955 
Jack R. Grieb and R. L. Kirkman* 
Introduction 
Breeding pair surveys were conducted within the period May 9 to 
June 2, 1955. During this time, ground counts were made in the Yampa Valley 
-and Brown's Park, and aerial counts in the South Platte, Cache la Poudre, and 
San Luis Valleys, and North and South Parks. Extremely poor flying weather 
made it difficult to finish aerial breeding pair counts this spring, the reason 
surveys were continued until June 2. 
Brood surveys were limited to four ''check" breeding areas due to an 
emphasis on summer banding this year. These areas comprise some of the best 
in the State, and serve as an indicator of conditions in the rest of the areas not 
included in this survey. The areas represented were North Park, Yampa Valley, 
Cache la Poudre Valley, and the San Luis Valley (San Luis Valley production 
estimated on the basis of data supplied by Refuge Manager, C. R. Bryant, froma 
study conducted by Biologist Fleetwood, on the Monte Vista National Wildlife 
Refuge). 
Weather and Water Conditions 
Climatological conditions for Colorado during the 1955 season reflected 
the effect of a severe and sustained drouth during the past several years. Some 
regions, especially in the eastern portion of the State, were almost devoid of 
suitable water areas for ducks at the onset of the breeding season. Late spring 
precipitation alleviated this situation somewhat; too late, however, to accommodate 
normal populations of ducks. Western slope water supplies appeared much 
improved over the past several years. Normal amounts of precipitation fell during 
the spring, and a near-normal snow pack was present in the mountains. 
* Cooperating personnel - U. S. Fish and Wildlife Service: Cecil S. 
Williams, Central Flyway Coordinator; Ray Buller, Asst. 
Regional Supervisor, Game Management; Ken Baer, Jim 
Robinson, and Dick Droll, Game Management Agents, Colorado. 
Colorado Game and Fish Department: Ronald A Ryder, Wild- 
life Technician; FE. Boeker and K. Milyard, Pilots; O. Scarvie, 
student assistant; R. Kirkman, Colorado Coop. Wildlife 
Research Unit; and Jack R. Grieb., Wildlife Statistician. 
