68 



NORTH AMERICAN FAUNA 67 



Month-old King Rails Inn-e at least four calls: (1) seep-seep-seep- 

 ( repeated) indicates o-eneral satisfaction and. particularly, acknowl- 

 edges the presence of others and notities them of its presence: (^2) 

 tah-ee! fah-ee ! (repeated), very high pitched and progressively lower 

 in vohime as sleep approaches, indicates relaxed comfort and sleep- 

 iness: (3) soo, tsoo [tsno) indicates lonely dissatisfaction: (4) keeJp- 

 keelp-'keelp-, a series of five or six hoarse notes in rapid sequence, ex- 

 presses protest. 



Thirty to sixty days 



During the second month the juvenal body plumage replaces the 

 natal down. The hrst juvenal feathers may be obscttred by down imtil 

 the yoimg rail is nearly a moiith old. but by the seventh or eighth 

 Aveek the development of nearly all of the body feathei^ is complete. 

 The plumages of four captive King Rail chicks developed at about 

 the same rate through the hrst 6 weeks, bttt the rate varied consider- 

 ably thereafter. 



The first evidence of change from the natal down plumage is the 

 appearance of white auricular tufts and pale juvenal feathers on the 

 underparts and flanks (figs. 27 and i2S). Feather development in 

 these areas during the fourth week is as follows : 



(1) The sternal region of the ventral tract : The pinfeathers are 

 pale bulf'y brown, and are tipped with natal down that is being pushed 

 out. 



(2) The crural tract : Pinfeathers are whitish with black down at 

 the tips. 



(3) The femoral tract : Feathers are approximately the same color 

 as those of the ventral tract. 



By the latter part of the fifth week the juvenal plumage of most 

 yoimg rail^ is developing in all body areas, btit feathering of the 

 crown and back of the neck may begin slightly later in some individ- 

 uals. The abdominal region, axillary region, chin, and upper throat 

 are whitish and contrast rather sharply with the dusk;\' upperparts. 

 particularly the lower back and rump. The dark brown feathers of 

 the upper back and humeral tract are well advanced, feathers of the 

 cervical region dower throat) are approaching a cinnamon color, and 

 the thighs and flanks are faintly barred. The upper and imdertail 

 coveiTS are making their appearance, and the anal circlet is sur- 

 rotmded by short white feathers. 



Quills began to appear the latter part of the fifth week on the 

 wings and tails of two of four captive birds. The primary and 

 secondary covens developed more rapidly than did the primaries 

 and secondaries. The linings of the wings developed last. 



By the sixth week the side of the head is whitish and faintly 

 washed with gray. A white siipercilliary stripe is beginning to ap- 



