754. =Townsend"s solitaire.= MYADESTES TOWNSENDII. Common resident; breeds from 8,000 to 12,000 feet; winters in mountains, though stragglers are sometimes seen on the plains. The author saw a pair on plains near Arvada, in company with a young, well-fledged bird.

756a. =Willow thrush.= HYLOCICHLA FUSCESCENS SALICICOLA. Summer resident; rather common; breeds in foothills and parks up to about 8,000 feet.

758a. =Olive-backed thrush.= HYLOCICHLA USTULATA SWAINSONII. Rare migrant.

758c. =Alma"s thrush.= HYLOCICHLA USTULATA ALAMae. Rare summer resident; in migration common.

759. =Dwarf hermit thrush.= HYLOCICHLA AONALASCHKae. Rare migrant.

759a. =Audubon"s hermit thrush.= HYLOCICHLA AONALASCHKae AUDUBONI. Common summer resident; breeds from 8,000 feet to timber-line.

759b. =Hermit thrush.= HYLOCICHLA AONALASCHKae PALLASII. Rare migrant; comes to the eastern edge of Colorado, just touching range of _auduboni_.

761. =American robin.= MERULA MIGRATORIA. Summer resident, but not common; some interesting questions arise in connection with intermediate forms.

761a. =Western robin.= MERULA MIGRATORIA PROPINQUA. Abundant summer resident; breeds from plains to timber-line.

765a. =Greenland wheatear.= SAXICOLA OENANTHE LEUCORHOA. European species; a straggler taken at Boulder by Minot.

766. =Bluebird.= SIALIA SIALIS. Rare summer resident; west to base of Rockies.

767a. =Chestnut-backed bluebird.= SIALIA MEXICANA BAIRDI. Summer resident; not common; western form, coming east as far as Pueblo.

768. =Mountain bluebird.= SIALIA ARCTICA. Abundant summer resident; breeds from plains to timber-line; in autumn roams up to at least 13,000 feet.