management routes were, in gome cases, selected in areas of 
high-density dove populations and did not yield representa¬ 
tive measurements of the breeding dove population density 
for the entire State. 
Randomly located call-count routes were first established 
and run in seven southeastern States in 1959. Since that time, 
routes have been located at random in 21 additional States and 
have been censused in two or more successive years. 
In 1965, in addition to the regular management routes, 
random routes were established and run in the States of Arkansas, 
Montana, New Mexico, North Dakota, Oklahoma, Texas, and Wyoming. 
The management routes will be dropped in 1966, but the random 
routes will be surveyed for the 1966 Mourning Dove Status Report. 
Randomization of call-count routes has now been accomplished 
in 35 States, including all those in the Central and Western 
Management Units. It is hoped that the remaining States of 
Michigan, Indiana, Maine, New Hampshire, Vermont, Massachusetts, 
Connecticut, Rhode Island, New York, Pennsylvania, New Jersey, 
Delaware, and West Virginia will be "randomized" in 1966. 
Long-term trends 
A base year has been selected for the purpose of showing 
long-term trends in each State's breeding dove population index. 
The average number of calling doves in the base year is used as 
a base figure from which to calculate succeeding year's averages. 
This is necessary because not all routes are censused each year. 
The percentage change in average number of calling doves from 
one year to the next is calculated only for comparable routes, 
i.e., for those routes that were run during both the current 
year and the preceding one. This percentage is then applied 
to the previous year's figure, already adjusted to the base 
year, to provide the current adjusted average number of doves 
heard calling. The adjusted number shows the true change 
from year to year as accurately as sample size allows. From 
this figure the breeding population index is calculated as 
described under "Weighting factors." 
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