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Fig. 1. Transects and strata for aerial waterfowl breeding population and production surveys. 
Pacific Flyway 
Data supplied by James C. Bartonek 
U.S. Fish and Wildlife Service 
The annual winter waterfowl survey was scheduled for 
2-8 January 1979 but was accomplished during 1-24 Jan- 
uary. The west coast of Mexico was surveyed during 
11-21 January. 
Unusually cold weather during December, coupled 
with persistent and sometimes deep snow cover, greatly 
reduced the habitats available to waterfowl in much of 
Montana, Wyoming, Idaho, Washington, Oregon, Utah, 
and Colorado. The reduced habitat prompted an atypical 
departure of birds from these areas before the survey 
period. In Nevada, habitat conditions continued to im- 
prove as water returned to the drought-stricken wetlands, 
and duck numbers were above those of recent years. In 
California, waterfowl were scattered because of an 
abundance of habitat created by rainfall and runoff dur- 
ing the survey period. Storms with rain and fog in the 
Central Valley prevented coverage from Chico to Red 
Bluff and in the Sierra Foothills from Modesto to Fresno 
which are mainly goose areas. 
Data for the seven western States entirely within the fly- 
way are compared with those from the previous year’s sur- 
vey. Border States are not included because this reporting 
did not distinguish between Pacific and Central flyways, 
and Wyoming did not conduct a survey. Generally, there 
was comparable coverage for all States, including Cali- 
fornia, where efforts in 1978 were affected by dispersal be- 
cause of rain throughout January. Comparability of 1978 
and 1979 surveys with other years, especially for Cali- 
fornia, may not be valid. 
Although the total duck numbers in 1979 differed little 
from last year (—5%) and the 10-year mean (—5%), 
there appeared to be continuing decreases in mallards 
(Anas platyrhynchos) when compared with last year 
(— 18%) and the 10-year mean (— 31%). Except for snow 
geese (Chen caerulescens), which showed little change 
from last year, most goose species showed decreases from 
last year and from the 10-year mean. This decrease could 
partly be attributed to incomplete survey coverage of the 
Central Valley of California, but other data suggest a real 
decline. By species, white-fronted (Anser albifrons), 
Canada (Branta canadensis), and cackling geese (Branta 
canadensis minima) declined 67, 15, and 30%, respec- 
tively, from 1978. Also, brant decreased 53% from the 
1978 survey and 9% from the 25-year mean. 
Total participation for 10 States and the west coast of 
Mexico included 105 personnel, 24 aircraft, and 47 autos 
covering nearly 56,400 km. 
