I cj 2 Allen and Brewster on Colorado Birds. [July 
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. Probably, 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 brought 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. Turdus migratorius propinquus. Western Robin. — 
Common. Occasionally seen in small flocks in April and the 
early part of May. 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 -propinquus by 
Mr. Ridgway) are as follows: Wing, 5.40; tail, 4.70; bill from nostril, 
.52 ; tarsus, 1.33. 
2. Turdus pailasi auduboni. Audubon’s Thrush. — A 
few 7 were seen about April 13, but no others till May 20, when 
for a few days they were quite abundant along the creek bottoms, 
having been driven down from 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 Turdus pai- 
lasi. * The extremes 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. 
