Percentage Oceupanc. 
No. of Dugouts Natural Dugouts 
Diatrict Inspected Arenas Fiooded Regular 
1 (Oxbow) a0 49,3 72.7 62,5 
2 (Sourie} S51 48] £3.3 24.2 
3 ( Wasckada) | 35 45.3 A6.6 25.0 
Ss (South Central) 16 40,2 23.0 25.0 
6 (Tiger Hills 10 45,4 nae 18.1 
7 (Agcinibolne Deita) a5 31.8 36.0 B.2 
L& (Rea River Velley) 120 ===> o.0 0,0 

The chief aqifference between vegular anc flosded dugouts appears to be 
that the shallow, flooded margins which ordinary dugouts lack, is highly 
attractive, if not an actual necessity, governing usace by ducks. This 
Augeeste to the waterfowl manager =. lead toward imtreving waterfowl habitat 
by attempting to obtain modificatione in dugowt constriction. These madifi- 
eations would be! 1) Excavating dugsute in natur&l depressions; 2) Flattening 
epoit banks; 3) Eeeping cattle from deetroying the adjacent cover, 
WHITEWATER LAKE DIE--OFF 
(4 special etudy by F. Grabam Csoch, Dominion *ildlife Service} 
An estimated £0,000 to 60,000 ducks died at Whitewater Lake, Menitobe, 
between duly 21 and September 1, 1949. Botulism 1s held responsible for moet 
of thig loss, the role of blue-green alga poisoning and other possible mortai- 
ity factors have not been determined. 
Whitewater Lake 1s a shallow sump of about 14,000 acres. It is one of 
the majer duck moulting and gathering areas in Canada. From early June to late 
September ite duck numbere are in the hundred thousand clase. Thie lake has 
All the requigites for a botulism area; extensive areas of ehore liable to 
flooding, “feather edges,” large deposlte of decaring organic matter and larze 
toncentreations of ducks. 
Whitewater Lake ales has an abundant growth af emergent and submerged 
vegetation. Heardstem bulrush and cattai}l occur as a nearly solid ring at a 
distance of 100 yards from the chore. This ring mergea with a Whitetop meadow 
at the eastern and weetern ends. The center of the lake is datted with lelands 
of bulrush, whitetop, and cattail, some of which are surrounded by dense beds 
of eago pondweed. 
A recent history of botullem leases at Whitewater Lake ile arc Follows: 
1946: 20,000" investigated by Smith and Hochbaum 
1946: 2,000 Hawkins, Sowls, Carrick 
1947; 8,500 Hawkins, (spec. report #5) 
1948; 1,000 Hawkins, Cooch {epec. report #60) 
1449: 50,000 - 40,000 Hawkina, Cooch et al 
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