shower recorded at lola on the 26th did not extend to the study 

 area. If each of these hens had laid one egg per day from May 23 

 to 29 inclusive, each would have laid seven eggs. 



Period of Incubation 



Schwartz (1945:66) observed two nests of the greater prairie 

 chicken from the beginning until the end of incubation. The eggs 

 were incubated 23 and 24 days. In my study a nest that was found 

 on May 24, 1951, contained eggs that were incubated at the time 

 of discovery and that hatched 22 or 23 days later. 



Success of Nests 



Assuming that each hen laid one egg per day, and that the period 

 of incubation is 23 days, the date on which the first egg was laid 

 was calculated for each nest. One or two eggs from each nest 

 were tested in water to determine the stage of incubation (see 

 Westerskov, 1950 ) . For nests that did not hatch, the date on which 

 the first egg was laid was estimated by this means. The fate of 

 each nest is described below. The nests are arranged in the order 

 of the estimated date on which the first egg was laid. All dates refer 

 to 1951. 



No. 1. Discovered on May 25, 13 eggs, hit with tractor wheel; salvaged 

 four eggs, one hatched in incubator on May 29. 



No. 2. Discovered on May 25, 15 eggs; on June 3 all had hatched at 

 latest by the day before. 



No. 3. Discovered on May 25, 13 eggs, hit with tractor wheel; salvaged 8 

 eggs, hatched in incubator June 1. 



No. 4. Discovered on May 25, 13 eggs, hit with tractor wheel; salvaged all 

 eggs, hatched in incubator June 1. 



There was one infertile egg among the 39 from nests 1, 3 and 4. 



No. 5. Discovered on May 25, 15 eggs; hatched June 6. At 8 A. M. on 

 June 6 the hen was on the nest with the complete brood. The disturbance 

 caused by my marking several of the chicks, the subsequent trampling about by 

 calves, and a heavy rain in the forenoon caused a loss of chicks as foUows: 

 one chick trampled in the nest; two stepped on by calves; one dead but no 

 obvious physical damage; one caught by the foot in heavy grass, alive but 

 barely able to move; one sitting quietly near the nest. The two that were 

 ahve were taken and successfully reared. The chilled one recovered within 

 20 minutes after being placed inside my shirt. These two were picked up at 

 3:15 P. M. when a hen was heard but not seen near the nest. 



No. 6. Discovered on May 28, 13 eggs; all hatched on June 3. 



No. 7. Discovered on May 26, one egg was cracked; the remaining 13 all 

 hatched on June 9; one hve chick left behind in the nest. 



No. 8. Discovered on May 24, 12 eggs; all hatched June 16. 



No. 9. Discovered on May 24, 8 eggs; all eggs gone without evidence of 

 cause on June 6. 



No. 10. Discovered on May 25, 7 eggs; female seen on the nest May 26; 



[26] 



