and blue-winged teal showed respec¬ 
tive decreases of 6 percent from 1964. 
The following comparisons are made 
to the 7-year average: Mallard +16 
percent, gadwall+83 percent, shovel- 
ers + 1 percent, pintails -40 percent, 
and blue-winged teal +30 percent. 
Only token numbers of American 
widgeon, and no green-winged teal 
were observed. 
Divers were up 66 percent from 
1964 and up 44 percent from the 7- 
year average. Compared to 1964, 
redheads and canvasback showed a 
respective increase of 16 percent and 
38 percent. In comparison to other 
species the total number of ruddy 
ducks was small, however, they 
showed an increase of 200 percent from 
1964. Scaup showed an increase of 
580 percent from 1964. This sharp 
increase is because of the very low 
population observed in 1964 and re¬ 
present only a 6 percent increase 
from the 7-year average. The in¬ 
crease in scaup undoubtedly reflects 
late migrants which may also have 
been the case with several other 
species. 
In summary, the total duck index 
for the tri-State area is up 20 percent 
from 1964 and up 17 percent from the 
7-year average. Total coot were up 
108 percent from 1964 and up 40 per¬ 
cent from the 7-year average (table 
B-36. 
The lone drake index of 67 percent, 
slightly lower than 1964 (67. 6%), in¬ 
dicates that the nesting progress was 
about the same as last year. 
Production indexes 
The 1965 tri-State brood index shows 
an increase of 2 percent over 1964, al¬ 
though fewer broods were observed in 
1965. This 2 percent increase is the 
result of more broods observed in the 
eastern and western strata which have 
high expansion factors and fewer broods 
observed in the central stratum which 
has a relatively low expansion factor. 
The brood index was down 45 percent 
from the average. Average brood size 
in 1965 was 4. 9 compared to 6. 0 in 1964 
and an average of 5.0. Coot broods 
showed an increase of 35 percent from 
1964 and 11 percent above the average 
(table B-37). 
The 1965 July water index showed an 
increase of 19 percent from 1964 and a 
decrease of -4 percent from the average. 
Vegetative cover was not a problem un¬ 
til the last few days of the survey. 
The late nesting index of +27 percent 
above the average and 44 percent above 
1964 indicates considerable late nesting 
attempts are in progress. Dabblers, 
which make up 88 percent of the total 
population, showed an increase of 37 
percent as compared to 1964. Of the 
dabblers, late nesting indexes for the 
particular species are listed as follows 
as compared to 1964 and the 7-year 
average: mallard +46 percent and 13 per¬ 
cent, gadwall +89 percent and 166 per¬ 
cent, blue-winged teal -13 percent and 
+20 percent. The late nesting index for 
divers showed an increase of 125 percent 
from 1964 and an increase of 4 percent 
from the average. Species represented 
were redheads and ruddy ducks. Red¬ 
heads showed an increase of 68 percent 
from 1964 and +31 percent from the 
average. Ruddy ducks were up 215 per¬ 
cent from 1964 and +9 percent from the 
average. 
NORTH DAKOTA 
Data supplied by Charles H. Shroeder 
North Dakota Game and Fish Commission 
Water and habitat conditions 
Water conditions in North Dakota at 
the time of the mid-July survey were 
better than they had been in 1964. The 
1965 water index of 6. 60 represented an 
increase of 22 percent over the 1964 
water index of 5.42, and a 72 percent in¬ 
crease over the 1958-1964 average water 
index of 3. 84. 
17 
