146 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



In mountain areas I have recorded it at 850 meters on Cerro 

 Campana, at 600 meters on the Cerro Azul, and at 500 meters in the 

 Serrania de Maje. Goldman found it at 550 meters on Cerro Pirre, 

 and to 600 meters on Cerro Bruja. Galindo secured one at 900 meters 

 at La Laguna on the slopes of Cerro Tacarcuna. There is definite 

 decrease in their number at these elevations. 



The Slaty Ant-shrike is particularly common from the Canal Zone 

 eastward, and through its curiosity is one of the forest species that 

 comes most frequently to attention. Individuals are found from 

 the low undergrowth of the forest floor to the shadows beneath the 

 crown of the taller trees. They move about slowly, often in such dim 

 light that they are seen with difficulty. Though they seek concealment, 

 at the same time their curiosity usually serves to draw them near at 

 hand. The song is a repetition of a single note, increasing in rapidity 

 and rising in pitch as it is repeated a dozen or more times, until it 

 terminates suddenly in a nasal zvank, that is completely different in 

 sound. In general it is similar to that of the other species of the genus 

 found in Panama but is less loud, though it carries well through the 

 forest. A nasal sound sometimes similar to that terminating the song, 

 and sometimes varied, is used as a call, with other chattering notes. 

 The male rests quietly while singing, but with wings and tail quiver- 

 ing from the effort of his rapid utterance. Males, and occasionally 

 females, puff out the back feathers to display the white bases, a mark- 

 ing that attracts attention in the dark shadows of their haunts. 



Though the pairs usually range alone, invariably they are attracted 

 by any excitement among their feathered neighbors. I have recorded 

 them regularly in the companies of birds over moving ant swarms, 

 though some observers have reported that they do not have this habit. 

 Their food is insects and other small animal forms. Two birds taken 

 by Goldman at Portobelo, Colon, May 25 and 30, 1911, that I 

 examined held fragments of insects, including the head of a mantis, 

 fragments of large cicadas, a grasshopper, fragments of camponotid 

 ants, and beetles, including cerambycids, weevils, and others. 



At our camp near Armila, San Bias, on March 11, 1963, a male 

 came into a dead tree, and presently a female joined him. I noticed 

 then that the male held a small insect in his bill. When the female 

 hopped up beside him he fed her, after which the two flew away 

 together. On Barro Colorado Island at dawn on the morning of 

 January 16, 1964, a male came to the insects around a light set to 

 attract them. He seized a large moth and then rested quietly. In a 

 moment a female flew over to him, took the insect and left quickly. 



