226 MiNOT on Colorado Birds. 



this song is not often to be heard. June 8, I found a nest and five fresh 

 eggs, as described in the Bulletin of July, 1880, but -with hasty measure- 

 ments a little in excess. The following is a more careful description. 

 The nest was in the roof of a cave, about ten feet from the ground, in a 

 niche, or pocket, veith an opening so narrow, vertically, that I could neither 

 look in nor introduce my hand. Fortunately, however, the rock was so 

 soft that I easily removed the bottom slab on which the nest rested. This, 

 as one looks down upon it, suggests the Eastern Wood Pewee's. It is 

 composed of twigs, stalks, and bits of leaves, surrounded by a few loose 

 sticks, and thickly felted with down, silk, and a few feathers. The hol- 

 low is 2| inches long, and scarcely half as deep. The eggs measure about 

 .70 X -50 of an inch, and are crystal white (rosy when fresh), sparsely 

 speckled and spotted, chiefly about the crown, with medium dull brown. 



10. Anthus ludovicianus, Lic/it. Titlakk. — A summer resident 

 above timber line, and occasionally below : at least one pair was estab- 

 lished about the highest of the Seven Lakes. May 28, a flock of more 

 than fifty appeared on Boulder Plains, in advance of a heavy storm, but 

 apparently were all gone the next day. The only song-notes I heard were 

 weak and tremulous, — nothing better than monotonous trills. On com- 

 paring these birds with Bay-winged Sparrows all about, I found them less 

 nimble in running. 



11. Mniotilta varia, Vieill. Black-and-white Ckeeper. Boulder, 

 June 1. 



12. Helminthophaga virginiae, Baird. Virginia's Warbler. — At 

 Boulder, common through the latter part of May in creek shrubbery, and 

 not shy ; at Manitou, in summer, the most abundant of its tribe, fre- 

 quenting (like the Cliestnut-sided Warbler about Boston) the oak-scrub, 

 where it is not easily caught sight of : occasional on the mountains. 

 Ordinary note, a sharp chip ; song, simple but various (deceptively so) : 

 common forms are cke'-we-che'-we-che'-we-che'-we, wil-a-wit'-wit'-wW (these 

 terminal notes being partially characteristic of Helminthophagce) and che- 

 tve'-che-ive'-che-tve', die' -a-clit' -a-che' . 



13. Helminthophaga celata, Z?a<VJ. Orange-crowned Warbler. 

 — I observed this species as a migrant only. At Boulder, it was not un- 

 common in the latter part of May. Its habits are generic, and its notes 

 and song much like the Nashville Warbler's. 



14. Helminthophaga peregrina, Cab. Tennessee Warbler. — 

 Boulder, May 31. With a characteristic slender tsip, but no song that I 

 certainly detected ; active, about twenty feet up, frequently hanging from 

 clusters. Also recorded by Mr. Aiken, further south. 



15. Dendroeca aestiva, Baird. Yellow "Warbler. — Abundant 

 summer residents, gathering, however, about civilization. Mr. Henshaw 

 speaks of their eggs in the West having a white ground : such specimens 

 I have several times found near Boston, where, however, their song varies 

 somewhat from that of the Colorado form. Writers have compared this 



