

Factory unit, the mother goose. (Photo by C. J. Henry) 



revealed some further information on the effects 

 of drought on duck production. Tlie water level 

 was unusually high in 1957, declined abruptly 

 during the 2 drought years tliat followed, and al- 

 most attained the 1957 stage in 1960. The resi- 

 dent duck population on the .square mile of pot- 

 hole habitat under observation showed marked 

 fluctuation during the 4-year period, increasing 

 the first 2 years, but declining 63 percent below 

 the peak in the third year and 29 percent below the 

 peak in the fourth year. Production thus showed 

 close correlation witli water levels during the 

 period of study. 



Production on the YeUowhrnfe. — Duck studies 

 on the Yellowknife study area. Northwest Terri- 

 tories, showed that productivity in 1962 was 

 .somewhat low as compared witli 1961, but varied 



considerably among species. Ix»cated within the 

 western edge of the Precambrian shield north of 

 Great Slave Lake, this area is in a part of the 

 northern transition forest, containing an average 

 of 15.7 natural jx)nds and puddles per square mile. 

 A late, prolonged breakup during the spring of 

 1962 resulted in moderately low water levels, with 

 about one-third fewer birds than were present the 

 previous year. Since far-northern breeding pop- 

 ulations of many species fluctuate invei-sely with 

 good water conditions on the prairies, most of the 

 decline in the Yellowknife region last year can be 

 attributed to improved conditions to the south. 

 Hi-eeding birds on the Yellowknife averaged 46.1 

 pairs per square mile, and production averaged 

 12.2 broods per squai'e mile, indicating that about 

 26 percent of the ])aii-s were successful in liatching 

 clutclies of eggs and tliat average productivity per 



12 



