546 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



streams, where their companions may be the Dipper and the Black 

 Phoebe. Torrent Tyrannulets, however, range alone, hopping and 

 running rapidly over gravel bars, sometimes even where a thin sheet 

 of water a millimeter or two deep spreads over a flat surface of stone 

 at the border of the stream. Insect food is picked from the gravel, 

 the water in shallows, or seized in quick sallies on the wing from the 

 sides of boulders or overhanging leaves. Such prey usually is 

 abundant, so that the requirements for food soon may be satisfied. 

 Then the birds rest quietly or preen their plumage on some open 

 perch, usually low down along the stream border. 



Feathers in this species are dense and soft over the entire body 

 so that they form a close covering. In birds taken for specimens, 

 where one had fallen to float in swift water, or even when it may 

 have been drawn under the surface for several minutes before it was 

 retrieved, the feathers were not saturated, so that only a quick shake 

 was required to dry them. 



As noted by Skutch (Pac. Coast Avif., no. 34, 1960, pp. 35^364) 

 their low, soft calls may be repeated as a twittering song, sharp 

 enough in tone to be heard above the noise of the rushing waters be- 

 side them. Skutch also records a dawn song, a repetition of "a single 

 note . . . heard above the babble of the current." He describes the 

 nest as built by both parents, usually on a branch overhanging a 

 stream, or less commonly, along the adjacent shore. The well-made 

 cup externally is of green moss, with a lining of feathers. The two 

 eggs in a set are pale buff, without markings. In 14 eggs the measure- 

 ments averaged 16.5x12.6 mm, ranging from 16.3-17.1x11.9- 

 12.7 mm. The female incubated alone, the period being 17 to 18 days. 

 Although the male did not assist, he remained nearby while his mate 

 was on the eggs, occasionally perching "beside or even upon the rim 

 of the nest to rest or to preen, and at times . . . would bill the 

 feathers of her head and breast in the most affectionate manner." 

 The young at hatching have light gray down through which the pink 

 skin shows, with the inner mouth color yellowish orange. Both 

 parents feed the young. These remain with the parents for five or 

 six weeks, and then locate elsewhere so that "only a single pair 

 patrols each reach of the rushing mountain stream." 



W. John Smith (Condor, 1971, p. 260) recorded a nest with eggs 

 March 26 to 28, 1962, on the G. Lewis property below Cerro Punta. 

 On March 13, 1965, at Bambito, below Cerro Punta, Dennis Sheets 

 directed me to a nest that he had found the previous day. This was 

 on an islet in the main Rio Chiriqui Viejo, placed in a clump of bushes 



