The Russet-backed Thrushes 
Nests were found in thickets, where they were supported by the inter¬ 
lacing of branches, or else saddled upon the inclined stems of vine 
maples, or in hr trees. In the last-named places, nests might be set against 
the trunk on a horizontal limb, but were more often at some distance from 
it. The birds were very sensitive about molestation before eggs were 
laid, and would desert a nest in process of construction on the merest 
suspicion that a stranger had looked into it. After deposition, however, 
the mother Thrush was found to be very devoted to her charges, and 
great confidence was often engendered by carefully considered advances. 
As an illustration of the difficulties of identification which beset the 
earlier ornithologists, we cannot cite a better instance than that offered 
by Dr. Cooper’s outstanding records of the nesting and distribution of 
this Thrush. Under the head of Turdus nannus Audubon, now recog¬ 
nized as our Dwarf Hermit Thrush, Hylocichla guttata nanus (Audubon), 
Cooper describes 1 the nesting of our Russet-backed Thrush as he knew it 
at Santa Cruz, the eggs being “pale bluish green speckled with cinnamon 
brown, chiefly at the larger end.” Under Turdus ustulatus Nuttall, known 
as “The Oregon Thrush,” the Doctor says: 2 “This more northern species 
is the exact counterpart of T. nanus in habits. I found their nests north 
of the Columbia, about the middle of June, 1854, containing four or five 
bluish white eggs, thickly speckled with brown.” Of Turdus swainsoni 
Cabanis (i.e., our Olive-backed Thrush) he says: 8 “The eggs are blue, 
with numerous reddish spots, and nests and eggs indeed are scarcely to be 
distinguished from those of T. ustulatus” ! Yet in i860 he had elsewhere 
recorded 4 of Turdus ustulatus Nuttall, “The eggs, unlike those of most 
thrushes, are white, spotted thickly with brown, and four or five in num¬ 
ber.” Possibly the good doctor had encountered a freak set; but if so, 
it must remain the envy of all oologists. 
No. 149a Olive-backed Thrush 
A. 0 . U. No. 758a. Hylocichla ustulata swainsoni (Tschudi). 
Synonyms.— Swainson’s Thrush. Eastern Olive-back. Alma’s Thrush 
(H. u. almce Oberholser, disallowed by A. O. U. Committee). 
Description. — Adults: Similar to H. ustulata , but grayer and more olivaceous; 
“color of upperparts varying from olive to grayish hair-brown in summer, from deep 
olive to slightly brownish olive in winter”; ground-color of underparts lighter buffy 
(yellowish buff or creamy buff); sides and flanks grayish instead of brownish olive. 
Young birds are decidedly darker, more blackish, above, with paler, less ochraceous, 
streaks; underparts with less extensive but more blackish markings; also much more 
1 Geological Survey of California, Ornithology, Vol. I., Land Birds, edited by S. T. Baird from the MS. and 
notes of J. G. Cooper, 1870, p. 5. 
2 Ibid., p. 6. 
3 Op. cit., p. 7. 
4 Rep. Proc. R. R. Surv., Vol. XII., Book II., i860, p. 171. 
