BIRDS OF COLORADO. 
125 
759. Turdus aonalaschkae. Dwarf Hermit Thrush. 
Migratory; rare. The exact position of this bird in Colo- 
rado is not yet definitely settled. The prevailing form of Hermit 
Thrush is auduboni^ but there is a mounted specimen of the 
typical Dwarf Thrush taken at Fort Collins the first day of 
October. H. G. Smith at Denver has taken one May 13, 1887, 
and one September 26, 1884, both identified by Ridgway, and a 
third that probably should be referred to this form was taken 
there October 5, 1892. These records make it sure that this 
form extends regularly during spring and fall migration as far 
east at least as the western edge of the plains. Concerning those 
sent to Mr. Ridgway, he says: “ Not quite typical, being a little 
larger than the average, but are much too small for audiiboni 
and altogether too gray and too slender-billed for pallasii.''^ 
(Nidologistj III. 1896-7, 76.) 
759a. Turdus aonalaschkae auduboni. Audubon’s Hermit 
Thrush. 
Summer resident; common. Sometimes called the Rocky 
Mountain Hermit Thrush because it is common and characteristic 
of that region. The most eastern record is that of Capt. P. M. 
Thorne and it is fairly common a few miles nearer the foothills 
during migration. Arrives the last of April and leaves the 
plains the last of May. Breeds in the mountains from 8,000 
feet to timber-line and occasionally to the lower foothills. At 
the lower altitude in southern Colorado laying begins early in 
June and is continued on the mountains to the middle of July. 
Returns to the lower parts in September and leaves the State 
about the middle of October. 
759b. Turdus aonalaschkae pallasii. Hermit Thrush. 
Migratory; rare. From the east the true Hermit Thrush 
comes only to the eastern edge of Colorado, thus just touching 
the range of audobo 7 ii. Two young-of-the-year were taken 
September 26, 1885, by Capt. P. M. Thorne at Fort Lyon, and 
identified for him by Mr. Brewster. 
761. Merula migratoria. American Robin. 
Summer resident; not common. The robins of Colorado 
shade from nearly pure mig^^atoria on the plains of eastern Col- 
orado to typical propinqua. There is no definite dividing line 
between the two forms, and for two hundred miles east of the 
Rocky Mountains, birds are often found that are a fair inter- 
mediate between the two forms. Birds that can be reasonably 
assigned to the eastern form occur as far west as the base of the 
foothills, and V. L. Kellogg mentions taking Robins in Estes 
Park that were as bright as specimens from eastern Kansas. It 
