Population changes are shown in table 2. The population 
index (average number of birds per route, weighted by the 
proportion of uncultivated land area in each State and 
Province) increased 7 percent in the Eastern Region and 
13 percent in the Western Region. The continent-wide 
change (both regions combined) from 1963 to 1964 was an 
11-percent increase (table 2). 
Most of the increase in population index occurred in 
States and Provinces where fewer than 10 comparable routes 
were covered each year. For example, although Ontario 
accounts for approximately 21 percent of woodcock breeding 
habitat in the States and Provinces where singing-ground 
counts are made, only 7 comparable routes were covered 
there in 1963 and 1964 . 
Previous analyses of singing-ground counts have shown 
that changes of the magnitude found in 1964 could occur by 
chance. Therefore, it is doubtful if the increase recorded 
in 1964 represents a significant change in size of the breed¬ 
ing population. 
Recommendations to cooperators 
Studies now in progress should improve the value of the 
survey, but usefulness of each count will depend upon its 
comparability with all other counts. Therefore, partici¬ 
pants should read survey instructions each year and follow 
them closely. Several routes covered in 1964 were not 
included in the analysis because stops on the routes were 
less than 0.4 mile apart. 
Random sampling in Michigan 
Routes used in the singing-ground survey to date have 
been established in areas where woodcock were known to be 
present. Such routes have been replaced from time to time 
as the habitat changed. Since routes are not uniformly dis¬ 
tributed in all types of habitat, counts from them probably 
are not representative of population density in the various 
States and Provinces. Furthermore, counts may not properly 
reflect changes in relative numbers of birds from one year 
to the next. 
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