584 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



by E. A. Goldman in 1911. On Barro Colorado Island it is seen 

 regularly, and also on the Achiote and Pipeline roads. Eisenmann 

 has seen it near Tocumen and on Cerro Azul. I have recorded it at 

 La Jagua, and near Chiman in the eastern Province of Panama. 

 There are various reports of it in Darien in the Tuira Valley from 

 the Rio Tuquesa and the Rio Chucunaque, Santa Fe, El Real, and 

 the base of Cerro Mali. 



They range, alone or in company with other small birds, from 

 rather low to high in the treecrown, in their active movement through 

 the leaves and small twigs suggesting a warbler or a vireo. Among 

 its companions, the short tail, plump body, and the black, rather 

 heavy, bill attract the eye. Their food, so far as I have recorded it, 

 has been small insects. 



The characteristic call is described by Eisenmann as a "high-pitched 

 repetition of whistled notes, usually five, going rapidly down the 

 scale, the whole phrase uttered in little more than a second." This 

 may be heard when the tiny bird is hidden among the leaves. 



Dr. Eisenmann and Major Chapelle, on August 15, 1954, on the 

 slopes of Cerro Azul, found a pair "building a nest in semi-open 

 woodland, about 12 meters above the ground in a tree of moderate 

 size. The incomplete nest, saddled in a small fork, partly shaded by 

 leaves, was a somewhat untidy flattened saucer of fine brownish twigs 

 (possibly leaf skeletons) mixed with bark shreds. One of the pair, 

 presumed to be the female, brought bits of bark which she shaped 

 with her body as she sat in the nest. The other bird, presumed to be 

 the male, came to perch a meter away." I have seen no description 

 of the eggs. 



Zimmer (Amer. Mus. Nov., no. 1126, 1941, p. 3) in a short para- 

 graph, was "doubtful of the validity of the genus Microtriccus which 

 differs from Ornithion only in its shorter tail and certain details of 

 coloration." He then listed Ornithion subflavum as its single species. 

 These changes were suggested without further discussion. The sug- 

 gestion, which has been accepted and followed in some recent publica- 

 tions, needs consideration. On careful comparison, it appears that 

 other differences separate the two groups generically, as in Ornithion 

 the distal outline of the primaries, especially at the outer end, is more 

 rounded, with the outermost relatively shorter, the primaries only 

 slightly longer than the longest secondaries, and these wing feathers 

 narrower in outline. The tail in Ornithion not only is proportionately 

 longer, being about four-fifths as long as the wing, but also is com- 

 posed of feathers that are actually decidedly narrower. The bird as 



