Interior of British North America. 41 
site for synonyms and reference to authorities, adopted that 
of Professor S. F. Baird in his admirable ‘ Report on the Birds 
of North America/ because that publication, being the result of 
much labour, must hereafter be looked on as a standard synopsis 
for reference on American ornithology ; and I will here mention 
that I am indebted to its author for material assistance in the 
identification of my collection, he having supplied me with 
specimens from the Smithsonian Institution of those species 
that were likely to be confounded together. 
Recurring to the geographical area to which the following 
notes refer, a glance at a map is sufficient to show that, being 
quite the heart of the northern part of the continent, its fauna 
may be considered strictly American; for, being well removed 
from both the eastern and western sea-boards, it ought not to 
include stragglers from either Europe or Asia. Some Pacific 
forms, however, occur, as might be expected, in the north-western 
corner, namely, on the Mackenzie River and its tributaries; for 
the configuration of the west coast north of the Columbia is such, 
that birds taking a direct north flight would naturally strike the 
upper waters of the Yukon River, flowing through the Russian 
territory, between which and the Mackenzie the lowness of the 
northward extension of the Rocky Mountain range is hardly a 
barrier; and consequently we find not only stragglers, but regular 
visitants from the Pacific frequenting the north part of the valley 
of the Mackenzie and adjacent Arctic shore. Such birds, there¬ 
fore, are here included, at least so many as are known to us; and 
I have sometimes mentioned the occurrence on the Yukon of cer¬ 
tain species (although that is beyond my bounds), in order to 
draw attention to them. For like reason also, I have noticed 
birds which have been found by American expeditions on the 
Upper Missouri ; but, like the last, they have only been referred 
to incidentally, and do not figure in the list in capitals, such 
being applied only to those ascertained to inhabit some portion 
of the “ interior ” as defined above; and no species which have 
been found only in Labrador and the north-east Arctic lands, 
British Columbia, or any part of Canada have been admitted; 
but I have drawn up this paper with the sole intention of sup- 
