^°^' 19^"^"^] HussEY, Spring Birds of La Plata. 397 



are not shy, and unite in small flocks, so that it is quite easy to study their 

 habits. 



To sing the Cachila mounts to a considerable height; then with wings 

 turned upward he begins his descent. He drops down a few feet, utters k 

 sweet " Cachila, "then swings upward a short distance, and a gentle hissing 

 sound is heard. He repeats this again and again until he reaches the 

 ground. I never saw one rise to repeat the song without alighting on 

 the ground. Thus the descent irom a great height is made up of a series 

 of little dips and rises, punctuated with bursts of song. 



61. GeothljTJis sequinoctialis cucullata (Lath.). — This little Masked 

 Warbler is quite common in bushy ground, and it even comes about the 

 houses in the Los Talas region. Its song, as Mr. Barrows says, is very 

 suggestive of a subdued warbling of our Purple Finch {Carpodacus purpu- 

 reus). 



62. Stephanophorus leucocephalus (Vieill.). — ^This beautiful Blue 

 Tanager is exceedingly shy, and though he may be heard often dm-ing the 

 spring, he is very hard to locate. The song is rather pleasing, although 

 somewhat jerky. 



63. Tanagra bonariensis (Gm.).^ Soon after my arrival at La Plata 

 in July my attention was called to a party of these pretty birds in an oak 

 tree in the observatory grounds. From that date until late in September 

 I found small flocks of them in the Bosque. The only note I heard from 

 them was a reedy call. 



64. Sporophila cserulescens (Bonn et Vieill.). " Corbatita."^ 

 These pretty little Finches appeared in numbers late in November, and 

 were abundant in the fields wherever the weeds grew tall. They were com- 

 monly seen in groups of four or five birds, both a;t Los Talas and at the 

 observatory, where I first saw them December 3. The song is a loud 

 cheery cry, slightly suggestive of the song of the Indigo Bunting. 



65. Spinus ictericus ictericus (Licht.). — This Goldfinch was but 

 seldom seen. It goes in small parties, and does not seem to differ greatly 

 from our Goldfinch in its habits. 



66. Sicalis pelzelni Scl. " Misto."— One of the most common birds 

 about the town is the Misto Sparrow. His song is very unmelodious; it 

 consists of shrill mouse-like squeaks pom-ed out in a continuous stream. 

 Whether this bird takes the initiative for itself in nest-buildmg I cannot 

 say; I have seen them breeding in the abandoned nests of the Ovenbird 

 and of the Lenatero, and I have spoken above of a case where they com- 

 pleted an abandoned nest of the Wren, and later shared it with that bird. 

 The eggs of this bird found in this last nest were marked with large spots 

 of deep brown on a blue ground, and averaged 1.95 X 1.39 cm. 



67. Sicalis arvensis arvensis (Kittl.). "Misto." — This Misto, 

 unlike the last, is a bird of the fields, and very rarely comes even to the edge 

 of town. Through the winter months it gathers in great restless flocks. 

 At this time they are not shy, but as the spring advances and the flocks 

 break up, they become more and more sensitive to intrusion. The male 



