as a somewhat open parkland type in which potholes are heavily ringed by aspen 
and willow, but the area surrounding the potholes is composed primarily of 
prairie. The district is devoted to both wheat farming and cattle ranching, with 
the study area itself located almost exclusively on land used as pasture. Potholes 
and lakes are frequent and generally of a depth sufficient to hold water except in 
severe drought. Annual rainfall averages about 17 inches, with 12.6 inches falling 
during dry 1950; 18.9 inches during a wet year, 1951. Throughout the period of the 
study, the district had excessive rainfall which resulted in a greater than normal 
precipitation during the growing season for a second year in succession. Field 
work was seriously hampered by ten days of rain between May 15 and May 31 
(2-1/2 inches) and 17 days of rain in June (9 inches). 
Soil Characters and Vegetative Aspects of the Study Area 
Areas 1 and 2 
Area 1 is located in the shallow black soils and Area 2 in the black soils 
of the eastern portion of the Province. Vegetation was similar to Area 3, which is 
described in the next paragraph. Agricultural activity is more concentrated on wheat 
raising so that aside from the aspen groves and their edging of buckbrush and willow, 
much of the natural ground cover has been destroyed by plowing. Where the natural 
vegetation has not been seriously disturbed except by grazing, the shrubby forms are 
in more dense stands than occur in Area 3. Larger and deeper lakes appear in this 
district than in any of the other study areas and severe drought is of less frequent 
occurrence than in the south. 
Area 3 
Area 3 is located in the black soils of central Alberta. The southern 
portion of this study area is only two miles inside the southern boundary of the 
parklands in the Kneehills. The district is subjected to winds throughout much of 
the year but evaporation is lower than on the nearby prairies because of the effect 
of the dense aspen and willow edgings which shade so many of the potholes. 
The emergent vegetation in the potholes of this study area is composed 
almost entirely of whitetop (Fluminea festucacea), sedges (Carex spp.), hardstem 
bulrush (Scirpus acutus), and cattails (Typha spp.). In normal and wet years, a 
heavy cover of prairie grasses carpet the ground. These are interspersed with 
dense stands of buckbrush (Symphoricarpos occidentalis), rose (Rosa spp.), wolf 
willow (Elaeagnus argentea), and saskatoon (Amelanchier alnifolia), all of which 
provide an abundance of nesting cover. Aspen (Populus tremuloides) and willow 
(Salix spp.) occur in groves surrounding the ponds and moist locations throughout 
the area. 

Methods 
Identical methods of making breeding population and brood counts were 
followed in all study areas. In each case, ground counts were made at a time 
which would coincide as closely as possible with the aerial coverage of the same 
area. 
