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Climatic Conditions 
The winter of 1950 varied from about average in a very few counties to very 
severe in many northern counties where the coldest January in 56 years was recorded, 
In addition to the cold, snowfall was heavy in most of the northern counties, 
Snow and freezing temperatures continued to the second week in May when the 
weather returned to "normal", Soil moisture was deemed adequate throughout the 
State. Potholes and reservoirs were filled that had been dry or very low for the past 
two years. At this time it was estimated that plant growth and pa crop planting — 
season had been delayed about two weeks. 
On June 7 and 8, frosts and freezing temperatures were prevalent throughout 
the State. Precipitation was heavy in all but'a few areas. Glasgow reported 4. 12 
inches for the week. The ''Highline" Area (Glasgow, Fort Peck and Medicine Lake) 
also reported from four to eight inches of wet snow during the period. The total 
effect of this late freeze and snowfall has not been determined, but in one area 
several nests were observed as abandoned. Waterfowl were known to be incubating 
as the first mallard brood was observed on May 22. Im addition, a great many paired 
mallards, pintails, and gadwalls were noted as late as June 20. This condition seems 
to be indicative of large-scale renesting attempts. 
Weather and water conditions have remained excellent for waterfowl 
production since the first week in June. 
Results 
Aerial trend counts were taken along flight lines established in the spring of 
1949. However, the census was conducted approximately one week earlier in 1950 
than in 1949. This may have some slight effect on the validity of the comparisons: 
The repeated use of a given calendar date as a basis for beginning aerial census 
injects a possible source of unknown error. This source of unknown error must be 
recognized, unless the time set for beginning the breeding ground census can be 
correlated with some biological phenomenon closely associated with the spring 
migration. 
A description of the trend methods and census routes may be found in the 
1949 report (Crissey and Others op. cit.). 
The data gathered from the Highline Glaciated Prairie Area and the 
Great Falls Piedmont Area (Figure 1) were analyzed by the application of the ''t'' 
test for significance. The computed value of ''t' was compared with Fisher's "Table 
of t'' in order to check the significance of the data obtained. This test was applicable 
since the same transects were used during 1949 and 1950 and resulted in paired data. 
D 
The f ul ed : te er 
e formula used was a 
Where: D= The difference between the means 
Ed = The standard error of the difference 
between the means 
Although more birds were observed in the Great Falls Piedmont Area, the 
1950 trend data did not show significance when the "t'' test was applied. The entire 
increase in birds per square mile (Table 1) was attributed to only one transect. The 
validity of attempting to apply, to the area as a whole, this increase in birds per 
square mile attributed to a single transect is doubtful. However, it can be said that 
the 1950 waterfowl population in this area was at least equivalent to and possibly 
slightly greater than that of 1949. 
