PROCEDURE 
The Call-count Method 
Call-count routes were established after field investi- 
gations in 1950-51 reported by Foote, Peters, McGowan, Kerley, Duvall, 
Robbins, and Wagner (1952). Doves heard calling and doyes 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. A report on the call-count method and pro=- 
cedures for randomly selecting call-count routes has been published 
by Foote, Peters, and Finkner (1958). 
The call-count survey provides the only population index 
currently available. 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 per- 
centage of the fall population is compysed of young of the year.. 
In calculating trends in the breeding-population index, doves 
heard calling has been a less variable index than doves seen. 
Additional research is needed to understand the relationship of 
doves heard calling to the actual population in various portions 
of the mourning dove breeding range. 
Weighting Factors 
To calculate trends in population indexes for units 
larger than one State, the base figure of average doves heard 
calling per route for each State is multiplied by the estimated 
area of dove habitat in the State. Dove habitat area was esti- 
mated in the 1958 Mourning Dove Newsletter and is listed in _ 
table 1. : 
In calculating band-recovery rates for local, immature, 
and adult mourning doves on a management-unit basis, the breeding- 
population index for a State was divided by the number of doves 
banded in each age group to obtain a weighting factor for each 
banded bird. Band-recovery rates on a State basis were calculated 
only for those States banding 100 or more doves in the age group 
of interest, and only those States were included in the calculation 
of weighted band-recovery rates for hunting and for nonhunting 
zones within a management unit (table 2). To obtain an average 
band=-recovery rate for a management unit having a hunting and a 
nonhunting zone, recovery rates for the two zones were weighted by 
the ratio of the-breeding indexes of the zones. 
