November^ 1944 



Bellrose: Duck Populations and Kill 



371 



order: shovelers, green-winged teals, pin- 

 tails, widgeons, mallards and black ducks, 

 ring-necked ducks, canvasbacks, lesser 

 scaups, ruddy ducks and gadwalls. 



9. In general, the duck species that 

 migrate through Illinois during the 

 early part of the fall migratory season 

 are the ones most easily killed. Ducks 

 of many species are most easily killed 

 during the early part ot the season, 

 probably because at that time juveniles 

 predominate m the population. 



10. The dates for the waterfowl 

 hunting season in Illinois should depend 

 upon what species of ducks need the 

 greatest protection, and whether the 

 hunter or the waterfowl population 

 should be favored. Cpen dates sug- 

 gested by this study are as follows: 

 For a 30-day season, November 1-30; 

 for a 45-day season, October 22-De- 

 cember 5; for a 60-day season, October 

 10-December 8; for a 70-day season, 

 October 1-December 9; for an 80-day 

 season, September 26-December 14; 

 for a 100-day season, September 20- 

 December 28. 



11. Although, in Illinois, the total 

 duck bag does not vary proportionally 

 with the number of days in the hunting 

 season, altering the length of the season 

 is one of the most expedient ways to 

 regulate the duck kill. 



12. Shooting hours, which were from 

 7 A.M. to 4 P.M., 1935-1939, from sunrise 

 to 4 P.M., 1940-1941, then from sunrise 

 to sunset, 1942, and from one-half hour 

 before sunrise to sunset, 1943-1944, 

 appear to have affected the flight habits 

 of cornfield feeding ducks more than the 

 kill of those ducks. Mallards, black 

 ducks and pintails feeding in cornfields 

 have changed the time of their daily 

 flights so that they still generally feed 

 before and after shooting hours. To 

 date there is apparently no evidence that 

 changes to earlier and later shooting 

 hours increased the duck kill; probably 

 the changes lowered the kill. 



13. Evidence derived from records 

 of the kill of ducks at one Illinois River 

 valley club that furnished good shooting 

 shows a close correlation between legal 

 bag limits in the lower figures and the 

 number of ducks killed per hunter-day. 

 The higher the bag limit, the less it 

 seemed to influence the duck kill; there 



was much less difference between actual 

 daily bag and legal limit when the limit 

 was 10 than when it was 25. The in- 

 dividual daily bag limit is an effective 

 regulatory measure in management of 

 migratory ducks in Illinois. 



14. Special protection has in some 

 years been given through reduced bag 

 limits to several species of waterfowl: 

 canvasbacks, redheads, ruddy ducks 

 and buffleheads. Some doubt exists 

 as to the effectiveness in Illinois of this 

 measure in reducing the kill of species 

 it is intended to protect. 



15. While wood ducks were killed in 

 considerable numbers even when given 

 complete legal protection, the regula- 

 tion permitting one such duck in bag or 

 in possession probably increased the kill 

 as much as two-thirds. The hunting 

 mortality rate of wood ducks in 1942 

 and 1943 was comparable to the kill of 

 other species of ducks under no special 

 bag restriction. Whether the produc- 

 tivity of the wood duck will keep pace 

 with the increased kill must be deter- 

 mined by closely checking the popula- 

 tion. 



16. In 1933, when use of bait and 

 live decoys was permitted, the kill of 

 ducks in the Illinois River valley was, 

 it is estimated, 8 to 1 1 times as great 

 in proportion to the population as in 

 1941, when use of bait and live decoys 

 was banned. The ban on the use of 

 bait and live decoys eliminated about 

 450 commercial dry-land pens in Illi- 

 nois. Most bottomland hunting clubs 

 were not seriously affected by the ban 

 on such practices. In 1941, there were 

 792 registered waterfowl hunting clubs 

 in Illinois, more than in the last years 

 of the baiting and live decoy era. 



17. The three-shell limit on shells in 

 gun appears to be a desirable restriction. 



18. In the 1938 1942 period, about 

 3 to 5 per cent of the migratory ducks 

 passing through the Illinois River valley 

 were taken by Illinois hunters. 



19. Restrictive waterfowl regulations 

 enacted in recent years have aided in 

 the survival of migratory ducks in 

 North America. Available data indi- 

 cate that over the North American 

 continent the proportional kill in the 

 past 10 years was about half that in the 

 previous decade. 



