BIRDS OP ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 117 



beating wings into the trees, or if found on high perches flew with 

 a few quick strokes of the wings that terminated in a short sail 

 in a direct line with long tail slightly spread and neck outstretched. 

 They alighted as easily as jays, ran quickly along the large limbs 

 and were lost at once to view. In the tops of trees they remained 

 motionless to escape observation, but were often betrayed by the 

 outline of the long tail or by a moving shadow caused by a head 

 concealed behind leaves. When flocks chanced to alight overhead 

 without having seen me approach the birds examined me curiously 

 as they uttered low whining calls. When at ease they sank on the 

 breast like pheasants and turned the head quietly from side to side. 

 When excited the long neck was extended to full length. Flocks 

 came to feed in flowering lapacho trees standing at the border of the 

 forest, apparently in search of the blossoms. 



The mating season, heralded by the harsh calls of the males, began 

 in September. Near at hand I found that the call began with a low 

 resonant note followed by a harsh cackle that changed in tone and 

 continued in rapid repetition for nearly a minute, thus, &m/?, ka 

 chee chaw raia taw, chaw raiu taw, chaw raw taio, a call that carried 

 easily for half a mile. At once this was answered by another bird, 

 another and another until perhaps half a dozen were calling from 

 near at hand. At this season they were heard many times at night. 

 On warm spring mornings the notes were heard on all sides — an 

 odd chorus, barbarous and uncouth, but attractive in spite ot its 

 harshness. When engaged in calling males sought a commanding 

 perch often in the top of some tall tree and were so engrossed in 

 their challenges that it was possible to stalk them without great 

 care. At times they were accompanied by females; copulation took 

 place in the tree tops. 



One morning I secured a bird just as a heavy rain came on. On 

 skinning it later I found the cavity of the large oil gland entirely 

 empty and judged that it had used the supply of oil to prepare for 

 the coming storm. 



The ancient Guarani name of Yacii-Caraguata given to this bird 

 in Azara's time has been abbreviated to Yacii though the species 

 is called more frequently by the term Charata. The Tobas in For- 

 mosa knew it as Gua che na (a cog-nomen of evident onomatopoeic 

 origin) and the Anguetes in Paraguay as Kin a tee. 



The trachea in females of this species is normal. In males it is 

 elongated to form a loop over the breast muscles on the right-hand 

 side that reaches to the keel of the sternum and then turns to pass 

 back and enter the thoracic cavity. From the lower end of the loop 

 a slender band of muscle passes back to insert on the connective 

 tissue overlying the pectoralis major above the end of the keel on 



