165 
Results 
The same transects and trend areas have been censused since 1949. 
(See Crissey and Others op. cit.) The comparative results of the 1951 and 1952 
aerial censuses are shown in Table l. 
All three major subdivisions of the State showed an increase in the 
number of breeding birds over 1951. However, the section of the Northern 
Glaciated Prairie which lies east of Glasgow showed a decrease in the number 
of water areas available for nesting birds (Table II). Both the Eastern and 
Sheridan Moraine of the Northern Glaciated Prairie are in this section. 
The central Highline, an area of early spring floods, showed an increase 
in breeding population of 25.98 percent. This area also had an increase in water 
areas amounting to 20.3 percent. Bowdoin National Wildlife Refuge and several 
easement areas are located in this section. Leon Snyder, Refuge Manager, had 
this to say regarding these areas (personal correspondence), "Our easement 
refuges in Hill, Blaine and Phillips Counties all overflowed their spillways, some 
of them for the first time since the establishment d the areas as refuges. Lake 
Thibideau in northern Montana, entirely dry for the past 17 years, obtained a 
12-foot water depth." Further, "On the whole, the writer feels that the spring 
migration was above normal and a far greater than usual number of ducks remained 
to nest in the general area," 
The southern Unglaciated Prairie Region is the largest habitat unit in the 
State. Stock water reservoirs constitute the bulk of the available water. The 
waterfowl density in this region is normally low. However, the trend areas in 
this region showed a greater percentage increase in breeding birds than any of the 
other regions (Table 1). In addition, the number of water areas on two of the trend 
areas was increased by 20 percent through the construction of new dams and the 
filling of areas that have been dry. 
The trend areas in the mountainous region showed a 13 percent increase 
over the 1951 breeding density. 
Grover Elgan, Refuge Manager for Ninepipes and Pablo Wildlife Refuges 
in the mountain area says, ''There seems to be an increase in the number of 
breeding waterfowl this year." 
Winston Banko, Refuge Manager of Red Rock Lakes, said about their 
breeding population, "Waterfowl breeding populations are roughly equal to, or 
slightly greater than was present last year." 
The species composition of the breeding waterfowl population was 
determined for five trend areas (Table III). There were notable changes in the 
percentage of species composition of each area. 
There was a very apparent increase of pintails throughout the northern 
prairie area. All trend areas showed a decrease in the percentage composition of 
shovelers and blue-winged teal. This trend is shown by figures from Bowdoin, 
Medicine Lake Refuge and Freezout Lake (Table III). Redheads also showed a 
trend towards increase in this area, A large percentage increase of scaups and a 
