Procedure 
Before actual field work was inaugurated in 1950, it was planned 
to investigate 3 methods. The roadside count had been widely used by 
wildlife technicians for doves as well as other gamebirds. The spot 
mapping method had been employed for determining actual numbers of 
territorial males of numerous species of birds in plots of known size. 
In the first area visited (Hagerstown Valley, Md.), roadside counts, 
and area population studies by the spot mapping method were made. Work 
was continued in southern Pennsylvania (York and Lancaster Counties) 
with the same two methods employed. 
Because of the short time available, the relatively large areas to 
cover, and the seemingly poor results obtained during the first two weeks, 
we proceeded to the third method. We began by counting calling doves at 
regular intervals along the road starting very early in the morning and 
again in the last three hours before sunset. Roads away from the main 
traveled highways were selected, and stops were made at every mile. Dur- 
ing these stops doves seen were listed as well as those seen while driving 
between the one-mile stops. 
Five minute listening time for each stop was first tried, based in 
part on H. Flliott McClure's studies in Iowa (Jour. Wildlife Met. 1939, 
3: 323-328). One mile intervals between stops were tested to avoid 
possible duplication of calling birds. 
According to previous arrangement Harold Peters met with Duvall and 
Robbins in Erie, Pa., June 6-8, and joined in making morning and evening 
call counts. Jt was then agreed that the three would concentrate on this 
method during the remainder of this particular investigation. 
Active field studies in 1951 began on April 5 and were terminated 
on September 141 insofar as the call counts were concerned. A standard- 
ized procedure of 20 stops of 3 minutes duration decided upon by agree- 
ment with several other investigators, was adopted; starting time was 
1/2 hour before local official sunrise. Counts were made by three 
observers on three separate routes on the same day of each week, except 
the ark one. Call count studies on area #3 were terminated after 
June 26. 
Roadside counts were begun on the census transects on July 27 and 
usually conducted by the three observers thereafter on the Monday evening 
preceding the regular Tuesday call count. After completion of the call 
counts on September 11, morning roadside counts were made over the same 
routes starting on September 18. 
Route #1 was censused by Chandler S. Robbins, Route #2 by Allen J. 
Duvall, and Route #3 by John W. Aldrich. 
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