214 UNIVERSITY OF COLORADO STUDIES 



Bombycilla cedrorum, Cedar Waxwing (619) 



One was taken by Bragg at Boulder on July 4, 1904 (now in the cabinets at 

 the state capitol). The writer saw three on Boulder Creek, September 11, 1910, 

 feeding on the fruit of thorn-apple. The species is not of common occurrence in 

 the state. 



Family LANIIDAE, The Shrikes 

 Lanius borealis, Northern Shrike (621) 



Winter resident; rather common on the Plains, and recorded once from the 

 Mountain zone, by Gale, in migration (October 17). Arrives, October 17-23 

 (4 records); leaves, March 7-19 (3 records). 



Lanius ludovicianus excubitorides, White-rumped Shrike (6220) 



Summer resident; rather common in the dry eastern portions of the county, 

 though seldom seen near Boulder except in migration. Arrives, April 18 — May 3 

 (5 records); latest fall date August 25. (Sclater gives April 9-14 [W. G. Smith] 

 for arrival at Loveland, a little north of the county.) The only record for the 

 mountains is one seen near Nederland (8,200 feet) by the writer, May 25, 1912. 

 Gale found eggs between May 20 and June 25. 



Family VIREO NIDAE, The Vireos 

 Vireosylva olivacea, Red-eyed Vireo (624) 



One was taken at Boulder by Bragg, May 30, 1904. It is rare in the sur- 

 rounding region. 



Vireosylva gilva swainsoni, Western Warbling Vireo (6270) 



Summer resident; common in the Plains, Yellow Pine and part of the Moun- 

 tain zone. Arrives, May 18-21 (2 records); leaves, August 23-28 (2 records). 

 Sclater gives May 12 (H. G. Smith) for Loveland. Nest-building has been 

 observed on the Plains, May 28 and June 3. In the mountains it is usually, if 

 not always, found in the deciduous trees — aspen groves. Widmann observed 

 the species near Estes Park from 6,000 to 9,000 feet. 



Lanivireo solitarius plumbeus, Plumbeous Vireo (6296) 



Summer resident; rather common in the Plains and Yellow Pine zones. 

 Arrives, May 18-21 (3 records); leaves, September 17-28 (2 records). There are 

 no definite nesting dates for the county. While found in summer in the cotton- 

 woods at least six to eight miles out on the Plains, it appears to prefer the pine 

 woods of the Yellow Pine zone. Widmann observed it from 6,000 to 7,500 feet 

 in the vicinity of Estes Park. 



