139 
Table 1. -- Total ducks by area, square mile, 
and-water area as determined 
from aerial surveys rae 5 
bad 
Sq. Miles : Ducks per : Total Wafer: Ducks per 
Sampled : Sq. Mile - /:~ Areas : Water Area 
Area 1949 1950 1949 1950 1949 1950 1949 1950 
Highline Glaciated | 314.9 306.1 5.5 8.3 455 1037 3.8 2.4 
Great Falls Piedmont . 137.1 .138.3 15.5 23.0 251 596 6.8 5.3 
South Unglaciated . Ton — 
Trend Areas ' 516 516 rea 1.1. 137 137 4,2 4.1 
Transects 89.4 124.4 3.1 6:7 93. 136 3.0 6.1 
Western Mountains , 3 
Trend Area A 9 9 54,0 34.1. 
Trend Area B ; 12 13 46.9 = 48,2. 
The value of "t'' for the 1950 data on the Highline Glaciated Prairie Area lies 
close but not within the 95 percent level of significance. ‘The data might have revealed 
increased significance if the area had been more completely covered. The flight strips 
were six miles apart and gave slightly better than a two percent coverage. This 
coverage was as intensive as was considered economically feasible. The data are 
significant at the 90 percent level, however, and upon this premise it is safe to assume 
that there was a valid increase in the breeding population. oar 
The census of the Southern Unglaciated Prairie Region (Figure 1) indicated a 
slightly larger population of breeding birds in 1950 as compared to 1949. A method of 
statistical analysis. has not been worked out for these data as yet, but an effort is-being 
made to develop one. The trend areas which have a combined total of 516 square miles 
showed a total of 576 birds in the spring of 1949 as compared with 556 birds in the 
spring of 1950. The difference of 20 birds is hardly significant and could be attributed 
to a sampling error. However, the transect data covering 124 square miles showed an 
increase of over 50 percent in total number of birds observed. ~ 
The waterfowl breeding population in the mountainous valleys, as determined 
from the trend areas, was down in 1950 (Table 1). The area involved in the -mountain- 
ous regions is considerably smaller than any of the other geological breakdowns of the 
State. : 
The total breeding ground population of ducks in 1950 was concluded to be 
slightly larger than the total population estimated in 1949. 
Although the species composition of waterfowl for the five important breeding 
areas of Montana indicate some changes between 1949 and. 1950, the percent of the 
total for most species shows an essential similarity (Table 2}. . The relative importance 
of the mallard, pintail, and blue-winged teal remains unchanged. - The usual exception 
comes from the mountainous area where the redhead again occupies second place in 
species composition. 
Large fluctuations of individual species are apparent in specified geological 
subdivisions. Mallards in the southern unglaciated prairie dropped more than 50 
percent in species composition for that area. The percentage of composition for scaup 
dropped from 17.3 percent in the western mountains in 1949, to 4.3 percent in 1950. 
However, the composition-of scaup in the Sheridan terminal moraine was almost the 
reverse (see Table 2). The percent composition of baldpates nearly halved in 1950 for 
the Highline and western valleys but a considerable increase was recorded for the 
southern prairie. 
