FLIGHT TRAILS SOUTH 



adult males. A few adult males in all species join with the juveniles in early 

 autumn but, except for the Mallard, the adult drake is an uncommon prize 

 in the hunter's bag on the prairie marshes. 



The adult female, which molts later than the adult male and in smaller 

 companies, does not make up aggregations of her own. When she recovers 

 flight after the molt of the wing feathers, she joins the young-of-the-year 

 and, according to the evidence of banding trap and hunter's bag, she migrates 

 with these juveniles, along with a lesser number of adult males.* Sowls 

 (1955:164) has summarized the adult-juvenile ratios of all ducks examined 

 in hunters' bags at Delta between 1938 and 1950 (Table 3). He found a 



Table 3. Age Ratios for 10,607 Ducks Examined in Hunters' 

 Bags on the Delta Marsh, 1938-1950° 



Species Adult Juvenile Ratio 



Mallard 



Gadwall 



Baldpate 



Pintail 



Green- winged Teal. 

 Blue-winged Teal . . 



Shoveller 



Redhead 



Canvasback 



Lesser Scaup 



* See Sowls (1955:164) for a complete breakdown of sex ratios. 



strong membership of adults in the migratory fall populations, species by 

 species. These samples were taken in late September and through October 

 each year, of birds shot between, just before, or just after migration. If the 

 bags erred from the true population ratios, the bias is probably toward a 

 heavier representation of juveniles, which fly less well and are not so wary 

 as the adults. I believe the strong ratio of juveniles to adults in Redhead 

 and Canvasback reflects their greater vulnerability to the gun in early- 

 season shooting. 



Although these hunter samples were taken at random from wild flocks, 

 it might be argued that adults and juveniles were shot from separate flocks. 

 It is true, indeed, that one finds bands made up wholly of young birds, while 

 some adult males keep to groups of their own. But in my hunting exper- 

 ience I have often taken adults and juveniles from the same flock when 



° In an exception to this rule, Mallards, especially their stubble aggregations, may show more 

 adult males than females in autumn bags ( Hochbaum, 1944 ) . 



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