1^2 Allen and Brewster on Colorado Birds. [J"ly 



value of the list consists chiefly in its being a careful record of 

 the arrival and relative abundance of the species coming within 

 this limited area of observation. 



The season, it may be added, was exceptionally cold and wet, 

 with frequent falls of snow on the foothills, which on a few 

 occasions extended to the plains, driving down, in several instan- 

 ces, birds which had previously retired to the foothills and lower 

 slopes of the mountains. Prqbably, also, owing to the unusually 

 inclement weather, many species arrived rather later than usual. 



It remains to tender our grateful acknowledgements to Mr. 

 Charles E. Aiken, Colorado's best known and highest ornitho- 

 logical authority, for varied acts of kindness, including many 

 valuable suggestions as to the movements and resorts of birds. 

 A few species of water birds, in each case duly accredited, are 

 included simply on the basis of our seeing them as brouglit to 

 him by collectors or sportsmen in the fresh state, the few locali- 

 ties near Colorado Springs favorable for water birds not coming 

 within the range of our excursions. 



1. Tuidus migratorius propinquus. Western Robin. — 

 Common. Occasionally seen in small flocks in April and the 

 early part of Ma3^ Observed nest-building May i. 



Most of the specimens taken are typical, but one, a fine adult male shot 

 May 20, has the terminal spot on the inner web of the outer rectrices as 

 large and purely white as in most eastern birds. The measurements of 

 this specimen (which fall within the limits assigned to frofinquiis by 

 Mr. Ridgwaj) areas follows: Wing, 5.40; tail, 4.70; bill from nostril, 

 .52 ; tarsus, 1.33. 



2. Turdus pallasi auduboni. Audubon's Thrush.— A 

 few were seen about April 13, but no others till May 30, when 

 for a few days they were quite abundant along the creek bottoms, 

 having been driven down trom the mountains by a heavy fall of 

 snow. 



Our seven specimens all come within the limits of size given for this 

 form by Mr. Henshaw, in his excellent paper on the races of Turdiis pal- 

 lasi.* The extreines are as follows : Wing, 3.72-4.05; tail, 3.08-3.20; bill 

 (length from feathers), .54-.56. 



Mr. Brown has lately expressed the opinion that "The difference in 

 length of bill exhibited by the three races of this species is almost micro- 

 scopic," and that "A much more tangible character, not mentioned by Mr. 

 Henshaw, lies in the disproportionate slenderness of the bill of the west- 



*This Bulletin, Vol. IV, pp. 134-139. 



