of the molt was noted for each and the remiges were measured ac- 

 cording to the same system as was used for the captive birds. 



Pterylosis of the greater prairie chicken is essentially the same 

 as that of the ruffed grouse as described by Trainer and Holm 

 (see Bump et al., 1947:76-90 and 741). Terminology used herein 

 is the same as that used by Trainer and Holm except that the pri- 

 maries are numbered from proximal to distal, the terms supra-ocular 

 and infra-ocular are used to denote the areas immediately above 

 and below the eye and that the term "cervical apteria*' is used 

 to designate the bare areas on the sides of the neck. 



Because the number of birds available for study was small it is 

 impossible to infer the probable amount of variation that occurs 

 between individuals, and thus to determine the extent to which the 

 data may be used in estimating the ages of birds in the field. 

 However, the results do form a tentative scale for aging immature 

 greater prairie chickens. In the following descriptions, emphasis 

 is placed on the changes that occur as the birds become older. All 

 measurements of primary feathers and secondary feathers are given 

 in numerical order. The number of each specimen is the catalogue 

 number of the University of Kansas Museum of Natural History. 

 The unnumbered specimens are the two captives. 



Fig. 9. Condition of the remiges of the greater prairie chicken at 

 hatching. Sheaths of juvenal primary feathers 1-7 and their 

 greater upper coverts are present. Sheaths of juvenal secondary 

 feathers 3-13 and juvenal greater upper coverts 1-13 are present. 

 All other remiges are present as natal down, and down feathers 

 remain attached to the tips of the sheaths. 



Twelve hours. No. 30473 KU (Figure 9). Natal down throughout, ex- 

 cept on the alar tract where there are, of the juvenal plumage, primaries 1-7, 

 greater primary coverts 2-7, secondaries 3-13 and greater secondary coverts 

 1-13; all juvenal feathers are sheathed and are of approximately same length, 

 7 nmi. 



[32] 



