July, 190S ANNOTATED LIvST OF THE BIRDS OF MESA COUNTY, COLORADO 165 



the most common birds found in the County. Found at all altitudes during the 

 summer and breeding abundantly wherever found. Its choice of a nesting place is 

 varied. I have found it in cottonwoods, cedars, scrub-oak, pine and aspen. 

 Winters along the streams in the lower part of the County, but not so plentiful in 

 winter as in summer. Its breeding habits are rather uncertain; fresh eggs may be 

 found during all of May and June. 



Phalaenoptilus nuttalli. Poor will. Summer resident, presumably common. 

 Owing to its retiring habits and nocturnal proclivities I have very little information 

 regarding this peculiar bird. One was collected for identification July 5, 1899, at 

 about 6500 feet in the Plateau Valley, and I have seen several others up to 8000 

 feet, but have not found it nesting, altho it undoubtedly does breed in the County. 



Chordeiles virginianus henryi. Western Nighthawk. Summer resident, com- 

 mon. A bird of the lower altitudes, much more common below 6500 feet than 

 above, in fact it is rarely met with above 8000. Arrives rather late in the spring, 

 seldom occurring in any abundance before May 1. Nests late in June, selecting 

 dry rocky ridges or sage brush flats as a nesting site. Departs for the south with 

 the first frosts. Mr. Sullivan's extreme dates of arrival and departure are May 8 

 and October 18. He says they are most abundant during the middle of August 

 gradually diminishing after that date. 



[Cypseloid.es niger borealis. Black Swift. Occurs regularly in Southwestern Colorado 

 and probably wanders into Mesa County from the south.] 



Aeronautes mel^inoleucus. White-throated Swift. Summer resident, of un- 

 certain occurrence. The writer has occasionally seen large flocks of these birds, 

 flying at a great height, pass over the Plateau Valley during the summer months, 

 but their occurrence is very uncertain, and I do not think the_v breed in the eastern 

 part of the County. My earliest arrival date is April 27, 1902. Mr. Sullivan says 

 a large colony breeds in the "ragged faces of the cliffs near the Book Cliffs Coal 

 Mine". Prof. Cooke states that they nest commonly at Whitewater. 



Trochilus platycercus. Broad-tailed Hummingbird. Summer resident, abun- 

 dant. The only hummer I have found in the County, altho T. alcxandri and S. 

 ruUis undoubtedly occur with greater or less regularity. Arrives early in May 

 (May 4, 1902, is my earliest arrival date), and breeds during June and July. 

 Frequents the timber along the streams from 6000 feet up and raises two broods in 

 a season and possibly three. I found them breeding abundantly on Buzzard Creek 

 at about 8000 and found nests containing fresh eggs, freshly hatched young and 

 fledglings just ready to leave the nest on the same day and within a radius of half 

 a mile. The nests are placed in pines, cottonwoods, and alders from 6 to 30 feet 

 from the ground and almost invariably near or over running water. One nest 

 found was built on a root protruding from a bank directly over and within 2 feet 

 of the swift running water of Buzzard Creek. I have noted it as late as October 

 15 but I think the bulk migrate in September. 



Selasphorus rufus. Rufous Hummingbird. Quoting Miss Eggleston, "irreg- 

 ular migrant. This hummer is not often seen, but occasionally will be met with 

 for a few days when the early flowers are out. 



[Tyrannus tyrannus. Kingljird. It is hard to understand why this well known bird has 

 not been reported by some of the observers who have furnished the basis of this list, but tho 

 special inquiry aboiit this species has been made the writer has been unable to find any record of 

 its occurrence in the County. It breeds in Middle Park, is known to occur rarely in Routt 

 County and probably occxirs occasionally in the Grand Valley.] 



Tyrannus verticalis. Arkansas Kingbird. Summer resident. I am not posi- 

 tive as to the relative abundance of this species and T. vocifcnins. Prof. Cooke in 

 his Birds of Colorado says of verticalis, "Scarcely found in the mountains, rising 



