200 UNIVERSITY OF COLORADO STUDIES 



Suborder Cypseli, Swifts 



Family MICROPODIDAE, The Swifts 

 [Cypseloides niger borealis, Black Swift (422)] 



Gale lists this species for the region but without data. Widmann includes 

 it in his list of birds seen at Estes Park (just north of the county) in the summer 

 of 1910 (Auk, 191 1). Other records for the state are from the southwestern part 

 only. 



Aeronautes melanoleucus, White-throated Swift (425) 



Summer resident; common locally in the Yellow Pine zone about the cliffs 

 of the canyons. Arrives, May 3-7 (4 records), earliest date April 10 (Gale); 

 leaves, September 19 — October 2 (3 records). Eggs have apparently not been 

 taken in the county. 



Suborder Trochili, Hummingbirds 

 Family TROCHILIDAE, The Hummingbirds 

 [Archilochus alexatidri, Black-chinned Hummingbird (429)] 



Gale lists this species for the county but does not give any data. It has not 

 been taken in the eastern part of the state. 



Selasphorus platycercus, Broad-tailed Hummingbird (432) 



Summer resident; common in the Yellow Pine and Mountain zones. Arrives 

 May 6-21 (5 records), one record for May 19 at 8,500 feet; leaves August 21 — 

 September 1 (4 records). The dates for eggs run from June 3 to July 17, the 

 latter being at elevations of 8,500 and 10,000 feet. The bird has been noted at 

 timberline in early July. 



Selasphorus rujus, Rufous Hummingbird (433) 



One was taken near Boulder by Gale. There was one in Mrs. Maxwell's 

 collection with no locality label (Henderson). According to Sclater the species 

 is rare in the eastern part of the state. 



Order PASSERES, Perching Birds 

 Suborder Clamatores, Songless Perching Birds 



Family TYRANNIDAE, The Tyrant Flycatchers 

 Tyrannus tyrannus, Kingbird (444) 



Summer resident; common on the Plains and reaching at least to the 

 upper limit of the Yellow Pine zone. Arrives, May 5-23 (8 records); leaves, 

 August 25-28 (4 records). Eggs have been found from June 7 to July 2 (Gale 

 and Blanchard). 



