PROCEDURE 
The Call-count Method 
Call-count routes were established after field investiga- 
tions in 1950-51 demonstrated the feasibility of the technique. 
These investigation were reported by Foote, Peters, McGowan, 
Kerley, Duvall, Robbins, and Wagner (1952). Doves heard 
calling and doves seen are recorded on a route 20 miles in 
length with listening stations one mile apart. Call counts 
begin one-half hour before sunrise and continue for two 
hours. Information on the call-count method and procedures 
for randomly selecting call-count routes was presented by 
Foote, Peters, and Finkner (1958). 
The call-count survey provides the only population index 
for doves currently available on a national and international 
scale. It has limitations and possible biases that require 
consideration and evaluation through further study. It is 
an index to the breeding population only and does not indicate 
production. This is an important limitation because a high 
percentage of an average fall population is composed of young 
of the year. In calculating trends in the breeding population, 
doves heard calling has been a less variable index than doves 
seen. Additional research is needed to understand the relation- 
ship of doves heard calling and doves seen to the actual population 
in various portions of the mourning dove breeding range. Several 
Cooperative Wildlife Research Units and State and Bureau Personnel 
are conducting studies of the call-count census method this year. 
Weighting Factors 
When combining data from several States to obtain breeding 
population indexes for management units or parts of management 
units, it was necessary to give appropriate weight to the data 
from each State. This was done by multiplying the average doves 
heard calling per route in each State by the estimated area of 
dove habitat in the State to obtain a breeding population index 
value. These index values for each State were then added together 
to obtain the properly weighted breeding population index for the 
combination of States. This weighting procedure recognizes 
differences between States both in dove density and the amount 
of habitat. Dove habitat area was estimated in the 1958 Mourning 
Dove Newsletter and is listed in table l. 
Pips 
