to fly far, were captured and examined in the field. Comparison 

 of these individuals and the specimens collected in the wild with 

 the captive birds, demonstrates that captives correspond closely 

 with wild birds both in growth and in development of their plum- 

 age. Comparison of the wild birds with the captive birds permits 

 the investigator to age the wild birds accurately enough to deter- 

 mine the time of the peak of hatching. 



As an aid to ascertaining the age of young prairie chickens, charts 

 illustrating the development of the primaries are presented in 

 Figure 10. Only data from captive birds of known age were used 

 in preparing these charts. For each primaiy an outline of the 

 fully formed adult feather is shown. Within this outhne, the con- 

 dition of each feather is shown at the age under consideration. A 

 feather which is growing, is indicated by the base of the quill being 

 blackened. Juvenal feathers are shown as stippled, and first-winter 

 feathers are shown as cross barred. The photographs (Pis. 2 and 

 3) illustrate the condition of the molt of the body at various ages. 

 These photographs are of captive birds, except Plate 3, figure /. 

 These figures demonstrate the close correspondence in body plum- 

 age of wild and captive birds with identical condition of molt of 

 the wing. 



Molt of the Adult Greater Prairie Chicken 



Adult males begin to molt after the cessation of breeding activity. 

 At this time they become secretive and reluctant to fly. No females 

 with broods were collected, but those without broods that were 

 examined corresponded to the males in the progress of molt. 



No. 30494 KU. Male. Taken August 25, 1951. Molt of wing 

 and body feathers complete; rectrices not molted; capital and pedal 

 tracts not molted; pinnae replaced and 35 mm. long. 



No. 29914 KU. Male. Taken September 15, 1950. All primaries 

 molted, 9-10 present as sheaths; all secondaries molted, number 1, 

 26 mm. shorter than number 2; rectrices not molted; sheaths of 

 new feathers on throat. 



No. 30491 KU. Female. Taken July 25, 1951. Primaries 1-6 

 replaced, number 6 a sheath; corresponding greater coverts re- 

 placed; secondaries 3-4 replaced; number 4 a sheath; new feathers 

 on coronal region; interscapular region with approximately 30 per 

 cent new feathers; posterior dorsal region not replaced; ventral 

 tract with new feathers ahead of wing, otherwise not replaced; 

 caudal tract not replaced. 



No. 20 M. F. B. Female. Taken on July 28, 1951. Primaries 

 1-5 replaced; secondaries not replaced; capital tract and anterior 



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