for the second or for subsequent years of life. The mortality rate 
calculated here for the mature inland-banded cormorants may, however, 
be affected by band losses that exist even under fresh-water conditions, 
: A further examination of first-year mortality rate is carried 
out by constructing an abridged life table based on 116 birds found 
dead and 73 found sick or captured under various conditions (table 20). 
We now have three estimates of annual mortality rates for this species 
(table. 21). If all the adults from age 2-3 breed and raise 2.5 young 
per pair to August 1 each year, the new sample population in table 20 
will theoretically produce 45.6 young. At the present time, we have 
no factual basis to assume that all double-crested cormorants begin 
to breed at this age. The calculation of a first-year mortality rate 
for this species must for the present remain in doubt. 
Table 20.--An Abridged Life Table for Inland~banded Double- 
crested Cormorants~-II 
Similar to table 18 but based on 73 birds found sick or captured 
by fishermen, and 116 reported as found dead. A few birds probably 
survived their capture. Age intervals start August 1 and are in 
years; mortality rates are per cent per annum. 
Age _— mn . — C) y Surviva ortality 
to be Birds Recovered Series Series Rate 
Studied Available (by age class) 1000 d,+(2) 
0-1 4,829 131 2761 39.6 68 
1-2 1,829 18 307 12.5 30 
3-h, 4,829 8 1.7 8.2 
he5 4,829 5 1.0 6.5 
5-6 4785 12 2.5 5.5 
6-7 4516 5 peel 3.0 2h, 
7-8 125 3 0.7 1.9 
8-9 3792 2 0.5 1.2 
9-10 359), 0 0.7 ! 
10-11 2943 2 0.7 0.7 = 
Table 21.--Estimates of Annual Mortality Rate in Double-crested 
Cormorants (expressed as per cent per annum) 
Source of Reports Shot + Found Dead Found Dead + Captured 
Where banded Warine iniand Inland 
Age Groups 
0-1 80 75 68 
1-2 37 39. 30 
later 39 22 2h 
