Tables 4, ~-Specisa Indsx 
{Routes 1 thru 4) {Routes 1 thm: 9} 
Number of Ducka / sq. mils Number of Tucks / sq. mile 
ecisg 2248 : ase 
‘Pinteil 4.49 4.72 8.48 9.48 
Blus-winged teal 2,50 2.18 4,26 9.05 
Shovelsr 2.03 1,27 2.93 4.58 
Mallard 2.44 1.93 3.64 5 Od, 
Scaup 47 7l  ,86 92 
Baldpats 1.15 .42 .f0 250 
Gadwall 1.05 1,08 2.21 4,08 
Redhead 11 18 1,02 LG 
Canvasback OF .,3) 165 57 
Ruddy LAG) evan te 96 
Green-wingesd toal -— Oe onl elt 
Altsough the pintsail nas been first in comparativs abundances for four years 
it was Just barsly so this ysar. The blue-winged teal, which has shown a trenan- 
douse inersass tha last two yaars in almost a atraight line relationship, has 
closely approached the pintail., The pintsil abundances, on ths other hand, shows a 
atrong tendency to follow a sigmoid curvs, that is, to nave increaesd slowly at 
first, then more rapidly and then to havs inersagsd more slowly or to hays leveled 
arr. 
The largsat incrsass in actual numbers was exhibited by the blua-wingsed 
taal and mallard, . 
With ths sxeaption ef the muddy duck, which showed a strons increases, the 
div-"" appear to bs lavsling off. A slight dscreass was racordsd for the canvas- 
back, Coots, which were tallied for tha first tims this year, constituted 8.2 
psresnt of all waterfowl obsarved. 
The species indsx curves for the pintail, shoyeller, redhead, and canvas- 
back all show 4 strong sigmoid tendency. This may b4 important, A sisneid 
relationship might indicates thet the peak in ths recent waterfowl in¢reasa may 
hays been reached, at least for soms specisa, and a gausral leveling aff or 
possibly a decrease may occur in the next ssvyerel years, 
Water Conditions 
Generally speaking, over post of the area, water conditions at ths time of 
Survey were hot as favorabls as they wera last year at the samo time. However, 
With ths axcaption of the Cotsayu arsa in northwestsrno North Dakota, conditions 
Wers not advoersas. 
159 
