

314 Warren, Birds of the Elk Mountain Region, Colo. [j^JJy 



Vireosylva gilva swainsoni. Western Warbling Vireo. — I have 

 but one record for this species, a female collected on Owens Creek, on the 

 northwesterly slope of Crested Butte Mountain, 9,500 feet, June 15, 1915. 

 It was collecting food when shot, so may have had young. It is quite 

 likely a fairly common summer resident and breeder. 



Dendroica aestiva aestiva. Yellow Warbler. — Summer resident, 

 common; breeding limit is apparently a little above 9,000 feet. A pair 

 had a nest at Adams's ranch on Muddy Creek in early part of June, 1903. 

 In 1915 Yellow Warblers were very common about the Hillside Ranch and 



1 discovered no less than six nests, all built in willows, 2 along the lake shore, 



2 near the outlet of the lake, and 2 in willows on the meadow; all these 

 last near running water. One nest was collected and I had a rather curi- 

 ous experience. It was found on the 9th and collected on the 16th of 

 June. I was passing on the morning of the last-named date and looking 

 into the nest saw four eggs. I returned about half an hour later with cam- 

 era, cut out some interfering twigs, set up and focussed, and then discovered 

 I had forgotten the plateholders, so went after them, returning in less than 

 ten minutes, and took two pictm-es. I saw the female about while doing 

 this. Then I went to remove the eggs and was surprised to find but one; 

 looking about the remains of the others were discovered on the gi-ound 

 below. Query: Did the bird destroy the eggs between the first and second 

 visits, or after I had set the camera and was absent after the plateholders? 



Dendroica auduboni auduboni. Audubon's Warbler. — Summer 

 resident and breeder; common. It breeds to at least 11,200 feet, judging 

 from locahties where I have seen the species in summer, and possibly some- 

 what higher. I saw one October 4, 1902, on the slope of W^hitehouse Moun- 

 tain, above Yule Creek. 



June 10, 1915, I found an Audubon's Warbler's nest at Hillside Ranch. 

 It was on a hill above the lake, in a Douglas's fir tree, on a branch about S 

 feet above ground, and 4 feet out from the trunk. Twigs hvmg below, 

 hiding it, and another twig projected over it above, hiding it from that 

 point of view. I was obliged to cut off the latter twig in order to photo- 

 graph the nest, and then the picture did not prove to be a success, thanks to 

 the wind. I discovered the nest by watching the female as she worked 

 about the tree hunting insects; wshen she disappeared on this branch and 

 did not reappear after some time I investigated and flushed her from the 

 nest. This is made of fine strips of dead bark on the outside, lined with 

 horsehair and a few feathers, some of which are Long-crested Jay's, and 

 others hen feathers. The nest is 3§ ins. diameter outside, 2 inside; and 

 the cavity If ins. deep. There were four eggs, very slightly incubated. 

 On June 13 I saw a female Audubon's in willows along the lake-shore not 

 far from where this nest was apparent^ collecting strips of dead bark for 

 building material. Possibly the pair were building a second nest. 



June 11, 1915, at an elevation of 11,200 feet on Mt. Emmons, in heavy 

 Engelmann's Spruce timber, where the snow was three feet deep and no 

 bare ground about, I saw at least two Audubon's Warblers about the 



