340 BIRDS OF THE REPUBLIC OF PANAMA — PART 3 



subject to considerable variation. Coupled with these are whirring 

 sounds made by rapid movements of the wings and a snap, somewhat 

 variable in explosiveness, made by abrupt contact of the stiffened 

 shafts of the wing feathers, especially of the secondaries. 



Males, during the prolonged breeding season, congregate in small 

 groups of three to eight or more in rather open undergrowth in forest. 

 Here, each male prepares a "covirt," a level space on the ground in 

 the undergrowth, roughly elliptical, in size approximately 50 by 80 

 centimeters. This is completely cleared of leaves or other cover, 

 and is the definite territory of one individual male. The courts of a 

 group of males may be separated by 3 to 60 meters, but, regardless of 

 distance, each with a varying amount of surrounding space is the ter- 

 ritory of a single male. At the approach of a female the male begins 

 to call and produce whirring and snapping sounds, until in final 

 climax he may be resting on the ground in his court with his "beard" 

 fully extended and the areas of yellow feathers expanded, while he 

 "assumes a rigid gaze-pose and holds it from several seconds to a 

 minute or more. After this rest ... he may jump rapidly forward 

 and backward across court, and no matter how short the distance, in 

 some invisible way, he turns in the air to alight, facing the point of 

 departure." Snow (Zoologica, vol. 47, 1962, pp. 100-101) describes 

 another action, seen only in part by Chapman, a slide in which the 

 male flies to a perpendicular branch where he clings head down, 

 with beating wings, and slides down turning as he goes to a hori- 

 zontal position. This is "a culminating phase of a courtship display" 

 preceding actual mating which may take place in the court or may 

 follow a mating flight. 



The female alone builds her nest, in which two eggs are deposited, 

 incubates, and feeds the young until they are grown. The nesting 

 season extends from February to August. 



The nest is a frail, shallow cup made, according to Jewel (in Stone, 

 Proc. Acad. Nat. Sci. Philadelphia, vol. 70, 1918, p. 268) of "strips 

 of plant bark, hairlike rootlets and grass stalks." The two eggs are 

 "grayish, heavily streaked longitudinally with varying shades of 

 brown." They measure 15.5 X 20.8 mm. In two collected on the upper 

 Rio Trinidad, Canal Zone, March 30, 1912, by August Busck, the 

 ground color is pale buff. One is heavily marked with narrow longi- 

 tudinal lines of dull reddish brown, intensified somewhat to form an 

 indefinite circle around the large end. It is somewhat damaged so 

 that it may not be measured accurately. The other has heavy longi- 

 tudinal lines, and blotches of dull reddish brown forming a band 



