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Weather and Water Conditions 
The over-all rainfall in Central Valley was normal for the 1954-1955 
season. However, most of the winter was dry, so that it took heavy spring rains 
to bring precipitation up to average. Parts of Northeastern California were 
extremely dry and some waterfowl areas, such as Horse Lake, and Honey Lake 
were either dry or in critical condition. 
Evidently the dry winter caused migration to start early with many 
birds moving up into the Tule-Klamath Basin in February. This early movement 
of waterfowl was followed by the late wet spring, which caused the birds that 
still remained in the Central Valley to stay longer than usual. In Northeastern 
California cackling, snow, and white-fronted geese stayed wellinto May. The 
first part of June found 30 white-fronted geese and 40 snow geese still present at 
Tule Lake. Canada peese started nesting about two weeks later than usual, with 
the first broods appearing after the middle of April. 
Scope and Methods 
Fundamentally the survey consists of an aerial census of the pairs of 
ducks present on the breeding grounds during the last half of May and the first half 
of June. Production is based on the number of pairs found, the relative nesting 
success, and the average brood size on each area. The latter two factors require 
considerable ground work and it is not always possible to conduct such surveys on 
each unit every year. An attempt is made to keep the data current on major 
areas. 
Goose production in California is confined to the northeastern section 
and involves only Canada geese, Since the goose nesting season is over when the 
regular survey flights are made in June, a special survey was made in early May 
to record the number of breeding pairs. The June survey was then used to 
determine production and fall populations. 
Insofar as possible the areas covered, census routes traveled, and 
methods employed have been duplicated from the pattern established in previous 
years. Census flights were made with a pilot and two.observers. On some flights 
a different observer was used than in previous years, but in all cases at least 
one of the observers had flown the census route before. 
All of the aerial transects were flown at elevations of 150 feet at 
speeds of 85 to 90 miles per hour with the two observers covering a ground strip 
one-eighth mile wide on either side of the airplane. Under these conditions 
experienced observers can accurately record species and sex of those ducks 
exhibiting divergent sex characteristics as well as note whether the birds occurred 
as pairs, singles, or groups of males. To obtain more complete information on 
Canada geese, in 1954 and 1955 an early flight (May 1 to 10) was made in North- 
eastern California to record the number of breeding pairs, singles, and groups 
(non-breeders) for this species. 
