VIREOS 
343 
The origin of the introduction, and the exact date, are unknown. It 
is supposed that they were originally escaped cage birds. At any rate, they 
are now well established about Vancouver, and are spreading without the 
environs. What their effect will be cannot be predicted. The introduction 
of a nearly allied Mynah, Acridotheres tristis, in the Hawaiian Islands, has 
not produced desirable results. At the best, it can only increase at the 
expense of some native species with which it comes into competition, and 
even if no worse effects follow, that will be enough to condemn it in the eyes 
of most of us. Outside of game-birds, there do not seem to be many cases 
where the introduction of foreign species of birds has had a happy ending. 
Usually introduced species fail to obtain a footing, or succeed too well, 
and either develop bad habits or replace native species of sentimental or 
economic value. Both the Canadian and the United States governments 
have prohibited the introduction and acclimatization of foreign species, 
and issued regulations controlling the practice; and it is hoped that no 
more species will be introduced. No introductions may now be legally 
made without special permits from the respective governments. This 
may not prevent such an accident as seems to have established this species 
with us, but will at least impede our knowingly importing such pests as 
the English Sparrow, or the European Starling (See preceding species). 
FAMILY VIREONIDAE. VIREOS OR GREENLETS 
General Description. Small, warbler-like birds, generally coloured in green and white 
with more or less yellow in softly suffused masses and without much definite marking. 
The bill is perceptibly notched and hooked at the tip (Figure 426) much 
like that of the shrike, but on a much smaller and lighter scale. 
Distinctions. The Vireos are most likely to be mistaken for warblers 
which in habit, size, and general coloration they resemble. The bills, 
however, are stouter, more strongly arched on the culmen, higher for 
the width, and more evidently hooked and notched at the tip. The 
Yellow-breasted Chat (Figure 455, page 364) has a bill that might 
answer this description in outline, but it is neither hooked nor notched. 
Field Marks. In addition to specific markings, which form the 
best guide to species, the vireos can be recognized by their warbler-like 
habits but slower and more sluggish movements, peering under leaves and gleaning from 
the branches and twigs with less activity. 
Figure 426 
Notched bill of 
Vireo (Red-eyed); 
natural size. 
The vireos constitute a small family of tree-top birds peculiar to 
America. Three genera occur in Canada, represented by six species. 
Economic Status. Economically the vireos may be treated together 
as they are similar in their food habits. Their food consists of 91 per cent 
of insects and the remainder of fruits that are almost without exception 
wild varieties. The insects taken are among the most harmful, including 
scales and other close-lying species that no birds but the careful, close- 
peering vireos ordinarily seek. They are among our most useful birds. 
631. White-eyed Vireo. le vireo aux yeux blancs. Vireo griseus. L, 5-27. A 
small vireo like the Warbling but of much richer green colour 
on back and with yellow loral mark and eye-ring; iris white. 
Throat and underparts almost pure white; strongly yellow on 
flanks; wings have two yellowish bars (Figure 427). 
Distinctions. White iris, yellow eye-ring and loral mark, 
strong yellow on flanks, and white breast and abdomen. 
Field Marks. The Solitary Vireo with pronounced white 
eye-ring has been occasionally identified as this species, but 
note that in that species the iris is dark brown, practically 
black. This species is too rare in Canada and too similar to 
other species to be recorded on eyesight observation unless the white iris is plainly seen. 
Figure 427 
White-eyed Vireo; 
natural size. 
