6£ 
Table 2h - RELATIVE VULNERABILITY OF SPECIES 
Upper Mississippi Refuge Area ONLY 

: PERCENTAGE COMPOSITION DURING FIRST WEEK OF THE WATERFOWL HUNTING SEASON ENTIRE 
:Popul-:Checked:Index :Rating::Popul-:Checked:Index :Rating::Popul-:Checked:Index :Rating ::Popul-:Checked:Index :Rating: 
Species :ation : Kill: * : ** s:ation : Kill: * x* s:sation : Kill: * > =ssation : Kill: * ~: ** ; 







. 
* . 
1.19 : 1.00 2 22.36: 23.40 1.04 : 1.00 es 37.60: LO. 30 
22.58: 21.98 -97 : 1.00 i 21.78: 26.11 
Mallard : : : : 1.07 , . 
Black 2 2.54: 1.01 : .39: .4O:: 1.51: 1.09: .72: .64 :: 2.24; 10k: .46: uh :: 1.91: 2.28 : 1.19 : 1.07: 
Gadwall : 65: SOT oe PA a TO aes SL olles = eon Vee Sed Oln eet SORES 6 7S ee 80s 0 Oh Se Os. 81/83. ot 1,09. es Ol s 
Baldpate : 17.27: 10.27: .59: .60 :: 40.38: 10.67: .26: .21 2: 24.11: 10.42: 1.43: .WL 2: 18.58: 8.30: .56: .52: 
Pintail 210.85: 4.yd: .bo: wn ts) 7639: 4.34: 658: 492: 9.83: 4.38: 4h: 142 2: 5.68: 7.04 : 1.23 : 1.14 : 
Gow. teal : 3elk: 6.77: 2.15 : 2.21 :: 4.11: 7.72 : 1.87: 1.57 :: 3.43: 7.10: 2.06: 1.98 +: 1.56: 5.97 : 3.82 : 3.57 
Bow. teal : 27.87: 48.31 : 1.73 : 1.78 :: 9.35: 28.71 : 3.07 : 2.57 2: 22.42: 41.53 : 1.85 : 1.78 :: 8.39: 18.14 : 2.16 : 2.01: 
Shoveller : o31: 223 670: «7223 Ae i -63:1.10: .92 3: 39: 36: .g92: .88 3: 225: .80 : 3.20 : 2.99 : 
Wood Duck : 11.34: 2.15 : .18: .18 2: 9.16: 15 70: 1.71: 1.43 :: 10.70: 6.84 : .63 : .61 :: 4.13: 7.46 : 1.80: 1.68 : 
Redhead : e213 238 5 3.45 2: 3.55 3: G6: 236: .78: .65 32: LOLS eg BTi th. 76: 291.098 ak fOr 2.70 S92 65%: 
Ringneck : 2.08: 3.60 : 1.73 : 1-78 2: 1.19: 2.30: 1.93 : 1.62 :: 1.82: 3.15 : 1.73 : 1.66 3: 6.60: 3.13 : 47: 4h: 
Canvasback : .14: .09: .64 : .65 :: 92 oe th ee SE ore SBE 80682 139927 32 er 2550s. 9 98 SBT 1: 34 3 
Scaup : Th: 89S 6522 538s 215s 58: .26: .21:: 1.16: 46: .39: «38 :: 12.88: 3.02: .23: .21: 
Goldeneye : t : oy ee ee Be ae See 03: - fF - ¢$ = 2 01% - ¢:- ¢ = ss 95: 15: .15: lh: 
Bufflehead ; Ol: 02 ; 2.00 : 2.06 t: Ges Ol: - > a4 «Oi. 02 : 2.00: 1.92 :: wkes sl Glos .£85-"3 
Ruddy : O72 <O9s4 1.28: * b.3l ss ell: 02; & “IB s =15 2 .08: SOT eT eG as 18: 16: .88: .82; 
Mergansers : 21: O02 : .09: .09 3: 08: sO. 0 Se 8 sO 38 me lt O02 ee aslo Sib ws 69: AO s <li Ses 



%* Index: obtained by dividing percentage of checked kill by percentage in the po ulation. 
** Rating: index obtained above was corrected to give mallards a rating of "1.00" tsatibe percentage in population is almost the same 
as the percentage in the checked kill). Other ratings show comparison to mallards: i.e., if mallards have an arbitrary rating of 
1.00, then green-winged teal with a rating of 3.57 has a vulnerability that is 3.57 times as great as mallards; blacks have a 
rating 1.07 times as great, etc. 
Note: In 1953, the season opened on October 3; in 1954 on October 2; from 1955 thru 1958 on October 1; and in 1959 and 1960, on 
October 7. This short delay made a big difference in species composition in the population. Note, for instance, that bald- 
pate increased from 17.27% of the opening population to 40.38%; while blue-wings dropped from 27.87% to 9.35%. Yet the 
apparent vulnerability of blue-wings was actually higher than with an earlier opening. Wood ducks, redheads, and canvas- 
backs have data complicated by whole or partial protection during some of the years of the study. 
