136 BIRDS OF SOUTH DAKOTA 
but never certain as to its identity. On April 20, 1920, a dead 
bird was found by Miss Bertha Nagle of Vermillion, which 
proved to be a Hermit Thrush. On close examination they can 
be easily separated from the abundant Olive-backed Thrush by 
the reddish brown tail and absence of any buff on breast and 
sides of neck. In size they are about the same. 
761. Rosin (Planesticus migratorius migratorius.) 
Few people think of the Robin as a Thrush. He is just 
“the Robin” to us—one of the common people, a good neighbor, 
a dependable friend, a thoroughly substantial bird citizen. 
The Robin, however, is the typical Thrush, the most 
highly developed of them all. Everything about this exceedingly 
satisfactory bird might well be characterized by the one word, 
substantial—its colors, its song, its nest, its young, its friend- 
ship, its prowess. Robins are found all over our State in sum- 
mer, and in the southeastern part loose flocks not infrequently 
remain all winter. Indeed in our coldest winters flocks of 
twenty or more have been seen on the University campus and 
in the wooded ravines at Vermillion. 
The Robin is the first bird in the migrating procession to 
arrive from the south. Even after his lusty song has been heard, 
snowstorms are not infrequent. At such times half a dozen may 
often be seen in the top of a maple feeding on the swelling buds. 
761a. WESTERN RoBIN (Planesticus migratorius propinquus.) 
A summer resident in the Black Hills and Harding County. 
Similar to the preceding but there is no white on the tail feath- 
ers. Feeding and nesting habits the same. 
766. BLueEspirD (Sialia sialis sialis.) 
The Bluebird, sometimes called Wilson’s Bluebird, is a 
close companion of the Robin in its spring arrival in the north 
and, like the Robin, occasionally winters in South Dakota. 
Length seven inches. Male: above, bright blue; throat 
and breast reddish brown; lower belly white; female: paler, both 
above and below. . 
