62 



NORTH AMERICAN FAUNA 67 



those of the California species ; it is pale buff, varying from "cream buff" to "pale 

 olive buff." They are sparingly and irregularly spotted, mostly in small spots, 

 with various shades of "vinaceous drab," "army brown" and "vinaceous brown" 

 and sometimes with a few spots of brighter browns. The measurements of 56 eggs 

 averaged 41 by 30 millimeters, the eggs showing the four extremes measure 

 44 by 32, 38.5 by 28 millimeters. 



I measured 20 eggs at Stuttgart, Ark. two from each of 10 nests. 

 The average measurement was 40.8 by 30.4 millimeters, with extremes 

 of 42.0 by 32.0 and 39.5 by 29.5. 



Table 9. — Clutch sizes in King Rail nests at three locations 



Number of clutches found 



Clutches with — Stuttgart, Northern Delaware 



Ark.i and central Valley 3 

 Ohio 2 



8 eggs 





3 



1 



9 eggs 





1 



3 



10 eggs 



3 



9 



3 



11 eggs 



7 



11 



2 



12 eggs 



3 



9 



4 



13 eggs 



1 



3 





14 eggs 



1 



1 



1 



Total 



16 



37 



14 



Mean number of eggs _ . 



11.2 



10.9 



10.6 



1 Meanley, unpublished. 



2 Trautman, 1940, p. 229; R. Bales, ms. 



3 Stone, 1937, p. 332; R. F. Miller, correspondence. 



Weight of eggs 



At Stuttgart, Ark., three eggs weighing 18.9, 20.3, and 18.8 grams 

 were marked on the day they were laid and were weighed on every 

 seventh day until hatching (table 10). The average weight loss was 

 0.47 gram during the first week, 0.83 gram during the second week, and 

 1.0 gram during the third week. The average total loss from laying 

 to hatching was 2.30 grams. 



INCUBATION 



The incubation period is about 21 or 22 days. Koberts (1936, p. 440) 

 stated that A. M. Bailey found the incubation period to be about 21 

 days. In Clay County, Iowa, Tanner and Hendrickson (1956, p. 55) 

 found it to be approximately 21 days. Incubation periods of four 

 Arkansas clutches were 21 days, 22 days, 22 or 23 days, and approxi- 

 mately 23 days. 



One Arkansas nest was under daily observation from the time the 

 first egg was laid on April 1 until the last egg hatched on May 4. 

 Eleven eggs were in the completed clutch, and incubation started 

 with the laying of the 10th egg on April 10. At another nest in 

 Arkansas incubation began on April 22 or 23, and the eggs hatched on 

 May 13 and 14. A nest at Mamou, La., contained 9 eggs on June 9 and 10 

 hatching eggs on June 30. 



