64 
wing, and graceful circlings — one instant hovering on rapidly beating 
wings, stationary in the air, as it searches for some tid-bit below, and the 
next dropping like a plummet with a sparkling splash — are constant 
delights to a seeker of the beautiful. Its shrill cry, harsh in itself, blends 
harmoniously with the soft surge of the surf and remains in keeping with 
marine surroundings. 
Economic Status. Though fairly numerous in suitable localities this 
species is too small to be seriously destructive. 
71. Arctic Tern. Sterna, paradisaea. L, 15-50 (Forking of tail 4*50). Closely 
resembling the Common and Forster’s Terns ( See Plates IV B and V A) in size and colour. 
Distinctions, The Arctic Tern has a little deeper greyish suffusion over breast and 
underparts than the Common Tern. Bill is red to tip, and feet and legs are very small and 
weak. It is not likely to be confused with Forsters on account of difference in range. 
In its colour characteristics it resembles the Common Tern very closely. 
Field Marks, An all red bill and little short legs, that make it look when standing as 
if crouching directly on the ground, and when walking it moves with a mouse-like glide. 
Distribution. The Arctic regions, south in the interior to the big lakes of Mac- 
kenzie region, and southern Alaska. It has been taken along the latter coast as far as the 
Canadian line, but rarely in British Columbia waters. We have records from the northern 
interior of that province, but none from anywhere east of the mountains. 
The remarks made under the Common Tern will apply to this species. 
It is remarkable that it has not been observed more often in our southern 
latitudes, for the species makes one of the longest migrations known. 
Summering north as far as land occurs, it winters as far south as the Antarc- 
tic continent. How it journeys there from the northwest coast without 
being noted en route is one of the interesting problems of American orni- 
thology. 
77. Black Tern. Chlidonias nigra. L, 10 (Forking of tail 0-8). The smallest of our 
common Terns, dark slate-grey, deepening to dull black on head, neck, and underparts. 
Distinctions. The above description is sufficient to separate summer adults. Winter 
and immature birds have a dirty white face, throat, neck ring, and underparts, and the 
§ rey above is suffused with more or less brown. It is, however, always considerably 
arker than corresponding plumages of other species. This fact, and the small size of the 
bird, should be sufficient to differentiate it at all times. Immature plumages retained 
throughout the following summer have been the basis of occasional records for the White- 
winged Black Tern, which will have to be removed from the Canadian list. 
Field Marks. Size and coloration make this species easy to recognize in life. 
Nesting. On slight elevations such as old muskrat houses or floating debris in wet 
marshes, nest of vegetable matter. 
Distribution. The American Black Tern is a bird of the interior, breeding from the 
Great Lakes region westward, north as far as Great Slave lake in the interior, and in south- 
ern British Columbia. 
SUBSPECIES. The Black Tern occurs in both Europe and America in allied sub- 
specific forms of which the European is the type. The American Black Tern C.n. surina- 
mensis is the subspecies with which we are concerned. 
This is a bird characteristic of the inland marshes, only rarely seen on 
the larger bodies of water, and throughout the interior prairies no extensive 
expanse of watery marsh is without it. Its general habits are much like 
those of the other Terns. It is less common in British Columbia than east 
of the mountains. 
Economic Status. The insect content of this bird’s food is probably 
larger than that of the other Terns. In the south it is known to consume 
the larvae of the cotton-boll weevil and it follows the ploughman of the 
west for the grubs turned up. Therefore, we may venture to state that it is 
probably actively beneficial. At any rate the fish it takes, if any, are mud- 
inhabiting forms of small economic importance. 
