satisfactory. In one instance 160 acres were censused in six hours. 



From May 12 to June 19, 1951, 16 nests were found in 610 acres 

 of unburned pastures and meadows. No broods indicative of earlier 

 nests were found, and no nests were found later than June 19 while 

 I was searching for broods with the drag. This tract of 610 acres 

 was given complete coverage and it is thought that all nests were 

 found, because the number of successful nests and the number of 

 broods found agreed closely. 



The value of studying nests is sometimes questioned, because of 

 the effects of the disturbance caused by the study. For example, 

 three nests were destroyed by my efforts to find them. My study, 

 otherwise, however, had little effect on the success of nests. No 

 nests were approached on foot, but only in a vehicle. This prac- 

 tice should have minimized any tendency on the part of predators 

 to follow human trails. Hens were difficult to flush from the nest, 

 and in one instance the hen did not flush until the wheel of the 

 truck passed over her tail and pulled out all rectrices and coverts. 

 This hen returned to the nest and succeeded in bringing off her 

 brood. In another instance a hen permitted the wheel of the truck 

 to pass within one foot of one side of the nest and the inner end of 

 the drag to pass within one foot of tlie other side without flushing. 

 In a third instance, the nest was destroyed by a predator only after 

 the hen had returned and laid two more egss. 



Rate of Egg Laying 



Little direct evidence is available as to the rate at which prairie 

 chickens lay eggs. Gross (see Bent, 1932:248) found in nests of 

 captive greater prairie chickens and in one nest of a wild bird that 

 the period of laying was approximately twice as long in days as 

 the number of eggs laid. Lehmann (1941:15) reported that the 

 same species (T. c. attwateri) in Texas normally laid one egg 

 per day until the clutch was complete, but that sometimes there 

 were intervals of one to three days between the times of egg-laying. 

 Indirect evidence obtained in this study proves that in some in- 

 stances egg-laying is at the rate of one egg per day. Two nests 

 found on May 29, 1951, each contained seven unstained eggs 

 plus some stained eggs. The stained eggs had been laid, or were 

 present, in a rainy period. The unstained eggs had been laid 

 after the rains ceased. Examination of the weather data for the 

 lola weather station, for which hourly readings of precipitation were 

 available, revealed that rain occurred each day from May 16 to 23 

 inclusive and ended early in the morning of May 23. A light 



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