374 
PASSERIFORMES 
Distinctions. Most likely to be confused with its near relative, the Baltimore Oriole, 
with which it may be associated in southern Alberta and adjoining parts of Saskatchewan. 
The adult male is easily distinguished from that species by its golden face and superciliary 
line; and conspicuous amount of white on the wing, the greater and adjoining coverts 
being mostly white, instead of white only on the tips of the greater. The female is too like 
the female of the Baltimore to be readily separated from it, but, in general, is paler, with 
few, if any, dark feather centres on the back, and the crown usually uniform yellow or 
golden olive. Juvenile males are like the female, and various intermediate stages up to 
the adult spring plumage occur. 
Field Marks. Throughout southern British Columbia this is the only oriole to be 
expected. In southern Alberta and adjacent Saskatchewan, either this or the Baltimore 
may occur. The black and orange plumage of the orioles is easily recognized. From the 
Baltimore, Bullock’s Oriole is distinguished by its golden face and superciliary stripe 
separated by a black line. The female in its dull yellow or orange and olive is larger than 
any other bird of similar coloration, except the Baltimore Oriole and the Western Tanager. 
It may not always be separable in life from the former except by geographical probability, 
but is best distinguished from the latter by its general warm orange or yellow tone instead 
of cold, dull green. The voices of the orioles are always distinctive, a rich contralto whistle 
with numerous musical themes, but the voice of Bullock’s Oriole is not so fine nqr so full 
as that of the Baltimore. 
Nesting. A deep bag of woven fibres, plant-down, hairs, and string hanging from the 
tips of long branches. Similar to that of the Baltimore Oriole. 
Distribution. Western North America. In Canada, southern British Columbia, 
cliiefty east of the Coast Range, and extreme southern Alberta and adjoining Saskatchewan. 
Very similar in habits and general status to the Baltimore Oriole, but 
rather less musically pleasing and less conspicuous than that species. 
Economic Stains. Food analysis of stomach contents in fruit districts 
shows that about 79 per cent of the food of Bullock's Oriole is animal matter 
and 21 vegetable. Lepidoptera, in the form of moths, pupte, and cater- 
pillars, are the largest item, but scales are a standard item of diet. Beetles, 
almost all harmful species, bulk largely in the food supply. Nine per cent 
of the vegetable food is fruit, largely cultivated varieties where they can 
be obtained. With its good record as a fruit-pest destroyer, only the 
prejudiced or particularly unfortunate sufferer will fail to admit that it is 
mostly beneficial. 
509. Rusty Blackbird, rusty grackle. le mainate rouiliJ:. Euphagus caro- 
linus. L, 9-55. Very like Brewer’s Blackbird (See Plate LXXIV A). About the size of 
the Red-winged and Brewer’s Blackbirds. All black or all black washed with rusty. Much 
larger than the Cowbird, but considerably smaller than the Bronzed Grackle. Eyes, 
straw coloured in both sexes. 
Distinctions. With size and plain black coloration, easily confused with Brewer’s 
Blackbird, but the spring male has green instead of purple reflections on the head. In 
autumn, the Rusty Blackbird is strongly overwashed with ruddy rusty above, solid and 
complete on crown; and rusty ochre below, strongest on superciliary line and throat. 
Females are solid smoky black, slightly darker than the female Brewer’s, and usually with 
faint traces of rusty on breast or back. The throat does not lighten to ashy. On the 
average the bill is slightly longer and more slender. Some specimens are very difficult to 
separate. 
Field Marks. Medium size, and solid black coloration, or black with much rusty 
overwash and decided ochreish superciliary line. Eyes in both sexes pale straw-yellow. 
Male recognized from Brewer’s by green instead of purple reflections about head; the 
female by having pale, straw-coloured eyes. 
Nesting. A bulky structure in coniferous trees or on the ground. 
Distribution. Eastern and northern North America. In Canada, across the continent, 
west to the mountains, breeding from northern tree limit to the edges of the prairies. 
Occasional in southern British Columbia in migration, where it seems to be increasing of 
late years. This is only a migrant throughout most of the breeding range of Brewer’s 
Blackbird. 
