flight from Redvers showed only 70 percent more 

 than in 1963. 



On the Lousana areti, reproduction was not ap- 

 preciably above that of 1963. 



Formal studies on the two areas, conducted 

 simultaneously since 1952, are being terminated 

 except for determination of water conditions in 

 196.5 and possibly 1966. A joint report on results 

 is being prepared by the Denver and the Xorthem 

 Prairie Centers. 



Witterfoicl p/'oducfMii in the Huhnrctlc. — A 5- 

 year comparison of productivity in certain duck 

 species was initiated iri 1961 on a study area near 

 Yellowknife in the Northwest Territories. A 

 principal objective was to detemiine the reproduc- 

 tive ability of ducks displaced by drought from 

 the prairies to the subarctic enviromnent of the 

 Far North. The 1964 suireys were conducted by 

 the Northern Prairie Center. 



The late spring breakup of the subarctic winter 

 is considered the most significant factor limiting 

 production, especialh* in normally early nesting 

 species such as the mallard and the pintail. These 



species, when forced northward from the i^rairies. 

 are near the period when they are physiologically 

 incapable of continued ^oa production, a circum- 

 stance that precludes significant renesting. Only 

 19 to 22 percent of the mallard and pintail pairs 

 produced a brood, as compared with a 27- to 33- 

 percent success for all duck species. Overall suc- 

 cess was low in 1964 because of heavy predation, 

 primarily by ravens. 



Mallards and pintails averaged 1.3 and 1.0 class 

 I ducklings per breeding pair, as compared with 

 late-nesting ringnecks and white-winged scoters 

 which averaged 5.9 and 4.0 class I ducklings per 

 pair. Local productivity by mallards and pintails 

 has been considered insufficient to maintain breed- 

 ing populations. 



Seasonal habit/it requirements of canvasbac^s. — 

 The Northern Prairie Center conducted in 1964 the 

 fourth consecutive year of field studies on the hab- 

 itat requirements of canvasbacks. Findings on the 

 Minnedosii. Manitoba, area indicated that prenest- 

 ing breeding pairs preferred the larger and more 

 permanent ponds having less than one-third of the 



Breeding flocks of Canada greese are being reestablished and breeding grounds are being improved or develc^)ed in 

 various localities over the country. Nesting structures, such as tbis straw-filled wire basket at the Patuient 

 Center, have been a particularly successful measure. (Photo by Frederick C. Schmid) 



17 



