November, 1944 



Bellrose: Duck Populations and Kill 



339 



to be the most vulnerable of Illinois 

 ducks, table 2. Their feeding habits 

 frequently bring them within range of 

 the hunter. Spoonbills do not furnish 



River valley. This is partly the result 

 of their habit of seeking the extensive 

 open water areas of large lakes and con- 

 gregating in tremendous rafts, which in 



Table 2. — The vulnerability, mortality and shooting pressure quotients for each of the 



important duck species or groups in the Illinois River valley, 1938-1942. The higher 



the figures, the greater is the vulnerability, mortality and shooting pressure. 



*Species with similar inherent wariness, flying, flocking and feeding habits were combined to reduce possible 

 error resulting from small proportional amount of data on certain species. The comparatively small population 

 and kill data for certain species was due to the enormous population and kill of mallards; some species have been 

 omitted because of insufficient data on them. The great range in percentage figures has caused some inexactness 

 in the smaller figures, especially those for the teals and shoveler, with a resulting distortion in the quotients. How- 

 ever, differences in quotients for the various species are large enough to be significant, and the figures are statistically 

 useful. 



as difficult a target as do teals, for their 

 flight is slower and less erratic. They 

 are undoubtedly one of the least wary 

 of ducks, frequently dropping into de- 

 coys without circling, and decoying to 

 the same blind after being shot at. 



As a group, diving ducks were found 

 to be less vulnerable to shooting than 

 were dabbling ducks in the Illinois 

 River valley, undoubtedly because of 

 the fact that most diving ducks con- 

 gregate in the open water of large lakes. 

 In Illinois, where duck hunting consists 

 almost entirely of marsh and lake shore 

 shooting, ducks at a distance from shore 

 furnish few shots. All diving species 

 were bagged in proportionally smaller 

 numbers than was the wary pintail, 

 table 2. Diving ducks are reputed to 

 be able to carry more lead than dabbling 

 species, and it is evident that many 

 crippled diving ducks escape capture 

 because of their diving ability. 



Lesser scaups, or bluebills, have a 

 lower proportional kill, table 2, than 

 any other diving duck in the Illinois 



size are next to those of the mallard. 

 As discussed elsewhere, the greater the 

 concentration of ducks the smaller is 

 the percentage killed. 



Canvasbacks, bagged in proportion 

 to their numbers more often than lesser 

 scaups, are credited with being more 

 wary, table 2. However, canvasbacks 

 are more readily decoyed along the Illi- 

 nois River than lesser scaups, perhaps 

 because they assemble in smaller flocks. 

 Canvasbacks frequent the inshore areas 

 of large lakes more than lesser scaups, 

 probably because of the occurrence 

 there of wild celery {Vallisneria spiralis), 

 duck potato {Sagittaria latijolia) and 

 other aquatic plants which form the bulk 

 of their food. Many hunters make a 

 greater effort to bag canvasbacks than 

 lesser scaups. 



Ruddy ducks, taken by Illinois River 

 club hunters in only slightly greater 

 proportion to population than canvas- 

 backs, are fast flyers, but they are un- 

 suspicious and fly at low levels across 

 the water, making them easy targets 



