A preliminary life table for mourni doves w i 
compiled for 297 juvenile birds banded from 1926 to ISO amekedli 
in the months of March to August inclusive. The results (table 
4) indicated a first-year mortality rate of 6); per cent and a 
mean adult mortality rate of 56 per cent per year, 
_This table was next checked by using 308 birds banded a 
juveniles from 1926 up through 19))] and expressing the results = 
birds reported dead per 10,000 banded. This abridged life table 
(not shown here) yielded a 62 per cent first-year mortality rate and 
a mean of 58 per cent per year for adults. 
A final check on the mortality rate for adults was obtained 
by analyzing a sample of 263 unaged birds banded from 1926 to 1937 
inclusive. With each year starting January 1, the mean mortality 
rate over a 9-year span of life was 58 per cent (table 4S). This 
particular sample was not checked against the banders' schedules 
but it does convince one that the mean mortality rate for adult : 
mourning doves has been close to 56-58 per cent per year. 
Table 45.—Survival in Mourning Doves Unaged at the Time 
of Banding 
Each year starts January 1; birds banded 1926-37; recoveries 
involve birds reported shot plus a small number found dead. 
Years after Bandi ne 3 G tT 6 8 9 Total 
Number dead 146 72 20 Th o Lo ii. . 263 
Alive at start of 
each year 263 117 4S 17 3 3 2 2 1 — 453 
Mortality rate 
(per cent per year) 56 #——-——_- 62 —____________} 58 
Age ratios and productivity 
| In a sample of about 100 mourning doves taken by pass 
shooting in New Mexico, Leopold (1921) found an age ratio of about 
1 young to 1 adult. He pointed out that, although this ratio could 
hardly be affected by juvenile vulnerability to the gun, it might 
be distorted by age-group differences in migratory behavior (a 
phenomenon still unproven in this species). In contrast to this 
estimate that the population doubles itself by autumn, McClure 
(1942, 1943) has concluded that the breeding population trebles 
itself in Cass County, Iowa. The age ratio implied in table 3, 
1.6 young per adult as of September 1 (that is, 297 + 168 = 1.58), 
ia intermediate between these estimates. It is also identical to 
that reported for 1162 doves taken by Texas hunters (Swank 1950). 
If successful broods elsewhere in the country are similar 
éo the 1.62 young per successful nest found by McClure (191), it 
would take close to 2 broods per year by each pair to balance the 
life-table populations examined in this study ([2 x 1.58] + 1.82 = 1.8). 
103 
