The BBS did not really get up and running in Alaska until the early 1980s. This histogram shows the number of routes surveyed each year.
Starting in the mid 1980's, larger numbers of routes were surveyed, but still the number of routes is very small relative to the area of interest and the road network is very limited and unlikely to provide a valid sampling frame for the state.
With these constraints in mind, we chose to present the results for Alaska. When evaluating these numbers, we suggest that:
(1) Please note the small sample sizes and very limited coverage within the state. The estimates do not represent the entire state, but only the limited area available for sampling.
(2) Estimates presented for the long-term actually represent the interval 1982-present. In particular, almost no data are available for the years prior to 1982, hence the 1966 - present trends are based almost entirely on post 1982 data.
(3) Annual indices for the survey are presented only for the recent years.
Users of the information must realize these limitations. USGS biologists in Alaska have been collecting data from a more extensive network of sites off-roads, and in future years more comprehensive information should be available for Alaska.