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nest. Uusally the birds so imposed upon accept the foreign egg without 
protest, at other times there is strong objection and final resignation. 
In a few cases, the nest is deserted or a new nest is built over the 
offending egg, as is sometimes done by the Yellow Warbler. On incubation 
an interesting case of adaptation is shown. The Cowbird’s egg usually 
hatches a few hours before those of the original occupant of the nest and 
consequently the changeling is strong and well grown when the proper 
occupants of the nest break their shell. It can monopolize the food, thus 
increasing the difference in strength, and is able finally to hoist its compe- 
titors from the nest to perish on the ground while it receives the attention 
that should have been given to the whole brood. Thus practically every 
Cowbird means the destruction of at least one brood of another species and 
probably the Cowbird must be considered one of the greatest enemies of 
the species imposed upon. Once the foster parents accept the intruding 
egg they do not make any distinction between it and their own. The 
Cowbird receives its name from its habit of following cattle, evidently 
attracted by the flies and insects which gather about those animals. 
Economic Status. From a study of their food, Cowbirds would seem 
to be purely useful birds. They consume large amounts of weed seeds and 
harmful insects and only small quantities of grain or fruit, the former 
largely waste and the latter wild. Their effect upon other equally useful 
birds, however, puts a different complexion on their activities. Practically 
every Cowbird raised to the fledgling stage means the elimination of a nest 
full of other species. Perhaps the economic effects of the changelings equal 
those of the individuals they displace, but the substitution cannot be looked 
upon with equanimity. 
497. Yellow-headed Blackbird. rFrr.—.’f&TOURNEAU A TETE JAUNE. Xantho 
cephalus tanthocephalus, L, 10. A Blackbird with white wing patches on the primaries, 
and yellow head, neck, and breast. Female similar, but brownish rather than black; 
brightness of yellow reduced, and white lacking on the wings. 
Distinctions. Above characterization unmistakable. 
Distribution. Western North America to northern parts of prairie provinces. 
Only of accidental occurrence in eastern Canada. 
A marsh or swamp bird rare in eastern Canada. 
498. Red-winged Blackbird. soLpImR BLACKBIRD. FR.—L’STOURNEAU A AILES 
RouGES. Agelaius pheniceus. L, 9-51. Plate XXVI B. 
Distinctions. All male plumages have at least suggestions of the red shoulders, though 
sometimes they are reduced to scattered spots of orange. The female is always dis- 
tinguishable from any other Blackbird by her sharply streaked coloration. 
Field Marks. The male is plainly characterized by its red shoulders, and the bird can 
be recognized in all plumages by its characteristic notes, the most common one, only 
uttered by the male, being well rendered into “‘ O-ke-lee”’ or “ O—-ke-ree”’ with a rising 
inflection at the end. 
Nesting. In well made structure of rushes and grass tied 2 or 3 feet above the water 
to reeds, cat-tails, or low bushes in swampy places. 
Distribution. As a species, the Red-wing is distributed over all of North America 
north to the limit of trees. 
SUBSPECIES. The Red-wings are divided into a number of subspecies. The 
common one in eastern Canada is the type form, the Eastern Red-wing. In the western 
end of Ontario we probably get the Northern Red-wing A. p. arctolegus from the central 
northern regions. It is characterized by somewhat larger size, but correct differentiation 
can only be made by the expert. 
No marsh in eastern Canada is typical without one or more pairs of 
Red-wings chasing each other or clinging to the cat-tails, the mal es 
