ties where prairie chickens are hmited to only part of the county, 

 proportionately fewer census areas could be assigned per county, 

 and one observer might cover more than one county. 



3. On one or more centrally located booming groimds the per- 

 son in charge of the census should observe the progress of events 

 until it is evident that the peak of mating activity is occurring. This 

 is indicated by the presence of a fairly constant and high number of 

 females appearing on the booming ground and usually occurs 

 early in April. The census should be conducted in the week fol- 

 lowing the peak of mating. In the week of the census, the same 

 booming ground should be observed to ascertain the number of 

 females that are present on it each morning. 



4. The actual census should be conducted for two hours in the 

 morning beginning as soon as there is suflBcient light to permit accu- 

 rate observation. When possible, the counts should be made without 

 flushing the birds and separate counts of males and females should 

 be made. With a little experience, the census-taker readily can 

 distinguish males from females by the more slender appearance 

 and the attitude of indifference in the latter (Schwartz, 1944). 

 Males ordinarily would be engaged in display, combat and pur- 

 suit activities, or might be squatting quietly at times when no fe- 

 males were present. With moderate to high winds, stops should 

 be made each half mile on a roadside census, the surrounding 

 terrain should be studied with the aid of binoculars, and any areas 

 not visible from the road should be visited. When conditions for 

 hearing are good, stops need be made at distances of only a mile, 

 and visual survey of unseen parts of the census area is unnecessary. 

 Complete coverage of each area is essential, or if an abserver can- 

 not cover the assigned areas, the part of each that was censused 

 should be designated. Preliminary surveys of the census areas 

 to locate booming grounds would facilitate the census, provided 

 that the census was made only in the assigned week, and provided 

 also that sole reliance was not placed on the booming grounds that 

 were found in the preliminary survey. 



5. All findings should be reported on standard forms to the 

 person in charge of the census. The number of males per square 

 mile would then be calculated. Total figures for the population of 

 the entire state would not be necessary provided no major changes 

 in the area occupied by prairie chickens occur. 



Considering the potential losses, among young birds, caused by 

 adverse weather, spring censuses are not sufficient bases for fixing 

 regulations. Such counts would be most useful in ascertaining the 



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