1890.] NATURAL SCIENCES OF PHILADELPHIA. 213 



17. Cinclus mexicanus Sw. Ameiiean Dipper. 



Seen along the Rio BLaiico. No specimens secured. 



18, Troglodytes aedon aztecus Baird. Western House Wren. 



Rather common. 



At the town of Chalchicomula or San Andres a number of speci- 

 mens were collected and a good idea of the avifauna of the region 

 was obtained. 



Chalchicomula is situated on a level plain covered with loose sand 

 or volcanic ash and is surrounded by numerous small cones of 

 volcanic origin while the great peak of Orizaba lies in full view a 

 few miles to the east. The plain is exceedingly dry and the vegeta- 

 tion is restricted to a few scattered bushes and scrubby trees, while 

 on the peak of Orizaba are the regular mountain forests of pine and 

 spruce. The altitude of the town is about 8,200 while the peak 

 towers up some 10,000 feet above the plain, reaching a height of 

 over 18,000 ft. above the sea level. 



The difference between the birds of this vicinity and of the town 

 of Orizaba, 4,000 ft. beloAV, was at once apparent. Only three spe- 

 cies were seen at both places, the Turkey Vulture, Lincoln's Spar- 

 row and Sparrow Hawk, and only the last of these was at all abund- 

 ant at Chalchicomula. Nearly all the species seen belonged to more 

 northern genera, and the absence of such birds as the Great-tailed 

 Grackle, Black Vulture and Red-eyed Cowbird was especially 

 noticeable. 



In the town itself the only birds observed were the House Finch, 

 Barn Swallow and Blue Grosbeak, while in the sandy country stretch- 

 ing toward the mountain the most characteristic species were Baird's 

 Wren, Black-eared Bush Tit, Curve-billed Thrasher, AVestern Chip- 

 ping Sparrow, and the two species of Towhee. On the edge of the 

 pine forest of the mountain a fine finch, Aimophila superciliosa, was 

 abundant. In the forest were found the Robin, Western Blue bird, 

 Slender-billed Nuthatch, Mexican Creeper, Mexican Chickadee, 

 Audubon's AVarbler, Mexican Snow bird, Sieber's and Sumichrast's 

 Jays. The spruce belt of the mountain was not well defined and 

 did not seem to offer any peculiarities in its avifauna. 



While several of the mountain species, such as Sumichrast's Jay 

 and the Mexican Snow-bird, were found on the plain some distance 

 from the edge of the forest, none of the characteristic birds of the 

 open country were met with in the wooded districts. 



