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2. Aerial counts of breeding-pairs on irrigated land types can be 
corrected to compare to ground counts, but the ratios between aerial 
and ground brood-counts were not consistent. Therefore, correction 
factors cannot be used to adjust aerial brood-counts. 
3. Ome more year of study is necessary on the Cache la Poudre 
township to determine if the differences in the average air-to-ground 
ratio for breeding-pairs between 1951 and 1952 were due mainly to 
the experience of the observers, or to inherent differences between the 
two years. 
