In Table 12, monthly averages are given for each stop over the 
three 1951 call count routes. The data indicate that there is no direct 
correlation of number of doves calling at any particular station with 
any particular period of the nesting season. 
Table 12.--Average Number of Doves Calling per Station (1951) 
| une | July | Aug. 
Station PC Zea Cae read Cone REA CR Av. 
1 re) 0.3 1.5 1.0 0.5 0.3 0.5 0.5 
2 2.0 2.0 h.0 6.0 0.5 3.0 3.0 0 
3 0 0.3 2.5 3.3 3.0 2e3 3.5 0 
h 2.5 2.3 3.0 2.7 1.0 1.3 2.0 0 
5 2.5 0 5.0 6.7 2.0 2.7 1.5 0.5 
6 2.0 2.0 1.5 2.0 2.5 1.7 2.5 1.0 
7 6.0 5.0 520 4.0 eS h.7 7.0 2.0 
8 3.5 3.0 heS 3.0 3.5 3.0 5.5 4.5 
9 3.5 3.0 2.0 1.7 h.O 3.3 h.0 3.5 
10 3.0 3.0 5.0 3 5.0 he3 5.5 1.0 
11 765 5.0 2.5 2.0 8.0 oe7 6.5 8.0 
12 eS h.0 2.0 1.3 3.0 2.0 eS 1.0 
13 1.5 1.7 0 0 1.5 1.3 2.0 1.0 
Uy 3.0 267 1.5 1.3 2.0 1.7 2.0 0.5 
15 0 3.3 6.5 h.3 5.0 3.3 2.0 2.0 
16 3.5 2.3 3-5 2.3 3.5 2.3 1.5 1.5 
17 1.0 0.7 1.0 0.7 3.5 3.0 3.0 0.5 
18 2.0 1.3 0.5 0.3 0 0 0 1.0 
19 2.5 1.7 3.5 2.3 1.0 0.7 2.0 1.0 
20 0.5 0.3 0.5 0.3 0.5 0.3 0 0.5 

Since the average number of times a dove called was 5.07 (Table 13) 
the total calls in Figure were plotted on a scale which was five times 
the scale used to plot the total numbers of doves calling. The pattern 
shown in this graph seems to indicate that there is a direct correlation 
between the total number of doves heard and the total number of calls 
recorded. If this be true it would seem that a population index could 
be predicated on the total number of calls as well as on the total number 
of doves calling. However, it is believed that the latter would give a 
more reliable index. Admittedly, errors can arise in interpreting the 
total number of birds calling, especially if there are a large number at 
any one station. On the other hand, background noises are almost con- 
tinually changing, and it is seldom possible to record accurately the 
number of times that all of the mre distant birds call in the prescribed 
period. In our experience a great many of the distant individuals are 
recorded only 1 to 3 times during the three-minute stop, being frequently 
obscured by the noise of a slight breeze, distant traffic, or the songs 
of other birds. 
