PROCEDURE 
The call-count method 
Gall-count routes were established after field investi- 
gations in 1950-51 demonstrated the feasibility of the technique. 
These investigations were reported by Foote, Peters, McGowan, 
Kerley, Duvall, Robbins, and Wagner (1952). Each route is 20 
miles long and has 20 listening stations located 1 mile apart. 
Call-counts begin one-half an hour before sunrise and continue 
for 2 hours. A record is kept during the survey period of all 
doves seen or heard calling along the survey route. Informa- 
tion on the call-count method and procedures for randomly 
selecting call-count routes was presented by Foote, Peters, 
and Finkner (1958). 
The only currently available dove population index, national 
and international in scope, is the call-count survey. The 
survey has limitations and possible biases which require fur- 
ther study. One important limitation is the fact that the 
survey provides an index only to the breeding population and 
does not take production into consideration. This limitation 
is“especially noteworthy since a high percentage of an average 
fall population is composed of young-of-the-year. 
As a basis for breeding population indexes, it has been 
found that doves heard calling have provided a less variable 
index than doves seen. Additional research is needed to 
understand the relationship 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 presently 
conducting studies of the call-count census. 
Weighting factors 
When combining data from several States to obtain breed- 
ing population indexes for management units or parts of manage- 
ment units, it was necessary to give appropriate weight to the 
