Water levels were moderately hicrh in most of 

 the larger potholes of Dickey and Stutsman Coun- 

 ties at the begining of the season as a result of 

 carrj'over from the previous fall. Above-average 

 rainfall in June brought about a rapid increase in 

 the number, level, and acreage of potholes, but 

 near-average rainfall during the rest of the season 

 did not compensate for evapotranspiration and 

 seepage outflow. Increased levels resulted in 

 openings in emergent vegetaticm, making many 

 type 3 potholes similar to tyi)e 4 and T) in their 

 physical aspects. 



Potholes in Ward County were in poor condi- 

 tion owing to lack of water carryover and snow- 

 melt. Some nnioff from rainstorms in June re- 

 sulted in temporaiT improvement, but levels were 

 further reduced as a result of below-average rain- 

 fall the rest of the summer. 



Waterfowl breeding ]X)pulations were 1 iwer in 

 1964 than in 1963. Thirty percent of the pairs 

 produced broods in 1964, as compared with 31 

 percent in 19G3, 42 percent in 1962, and 29 percent 

 in 1961. The total number of class I ducklings on 

 the 3 areas was 927 in 1964, as compared with an 

 average of 848 the 3 prior years. Production, 

 therefore, was considered "about average."' 



Most waterfowl use was on fresh to slightly 

 brackish potholes. Type 4 and 5 potholes were 

 most imix)rtant ; however, a significant amount of 

 use was on type 2 potholes where deeper water 

 created openings. Potholes of more than 5 acres 

 were not important duck-rearing areas, and brood 

 use was correlated with increasing water depths. 

 The highest density was on potholes 48 to 60 inches 

 deep; no broods were found on potholes less than 

 12 inches deep. 







•:s^-^^'aMBt* je^* 



•.fAVHirv^CSi 



Bureau biolupisis are studying waterfowl pnKluction in the Yellowknife counrry of the Northwest 'ierntories. in whicJi 

 four typical habitat types are illustrat<><l. Marsh-bordere<l shallow pond (top. left), small ix)nd surrounded by 

 a floating sedge mat (top. right), a .steep-banked, rock-bordere<l i>ond (bottom, left) and a 92-acre lake, largest 

 on the area (bottom, right). The biologist is engaged in a duck-brood count. (Photos by H. W. Murdy) 



775-624 < 



19 



