LAT 
Table 63.~—-Variations in Mallard Mortality Rates Based on Hunters' Reports of Adults 
Banded in the Mississippi Valley During the 1920's 
These birds were banded by F. C. Lincoln in Illinois and John Broeker and L. V. Walton in 
Missouri. As in table 62 the last column on the right is the annual mortality rate for 
first year indicated, based on single cohort only; mortality rates at bottom of table are 
based on all banded cohorts available. Durability of bands is unknown. 
‘When Mortality and Survival Data Classified by Years (Sept. 1 - Aug. “Mort. Rate 
Banded ss“ “(sO OS 8G OT 188 rT ee 
Y 8 ayy tQy 139 9° 31, 1 A ~ Tota xl 








1922 Ill. 92 51 20 11 2 2 2 2 2 @ = = = = 181 S51 Z 
1922-23 Mo. 30. ee ee eee 43 a 
Spring 1923 Mo. 173 127 h2 12 9 8 2 WH 2 = 2 = - = =-_=-=_1._._ 382 _ Us 
Subtotal 396 Is? “65 “2h “IS IO ~ F-~ STH WS TWTITA-~ STITT IT ITT FS 7 UZ 
Spring 192), =le7 Be Be Is my fk eS DY A ow we oS « 22h 57 
Spring 1925 - -=- 29 18 9 5 5 2 2 2 2 es = = = 72 = 
Spring 1926 oo eRe IS OS 6 So 2 Be ee oe 6g - 
1926 111. - - - =- 77 79 2 23 UD 7 3 2 - = - 228 3 Z 
Tot -— «= -_ 
Mean Mort. 
Alive at Start of fener Season (September 1) Rate All Ages 
1922-3 it 2 wt 1211 50 ¢ 
Spring 192) = 28 97 62 36 23 13 8 § 2 1 = = = » hyo 48 ¢ 
Spring 1925 - - 72 43 25 1611 6 &§& 2 = = = = = 179 LO % 
Tee cs. Le, Bes 218 i6 23 2 ae. ee 
Fall 1926 - |= = = 2281 Be OE A ee a Se eS 
Tot } 606 534 297 223 | {ie a ae Se SE: L6.5% 
iets Mortality Rates ie ae per rants - Sep : | 
All Cohorts 49 58 43 39 35 (U7) (35) 46.5 
Cohort 1922-23 9 59 51 - - ea 
Cohort 192k - 57 - - - 2 
Cohort fall 1926 - = = = 3h 52 = , 
