56 



Field Marks. Except the even red coloration of the bill, which is not an absolutely 

 reliable guide, there is no field mark that can be described by which this species can be 

 recognized with certainty. As in eastern Canada it is a sea coast species, it should be 

 recorded on eyesight evidence only where it is known to occur commonly. 



Nesting. Depression in sandy beaches. 



Distribution. Nearly cosmopohtan, but of eastern and Arctic distribution in Canada 

 and rarely if ever seen in the Great Lakes region. It is notable from havin-z; perhaps the 

 greatest migration range of any species of bird. Though found in summer north close to 

 the pole, it winters as far south as the Antarctic continent. 



The remarks made under the heading of the Common Tern will very 

 well apply here, bearing in mind that this species is regularly onl}^ of extreme 

 eastern and Arctic distribution. 



Economic Status. The small size of the fry it takes and the known 

 abundance of such fish in the sea, renders this species as harmless as any 

 of the other Terns. 



77. Black Tern. fr. — la sterne noire. Hydrocheledon 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 diagnosis is sufficient to separate summer adults. Winter 

 and immature birds have a dirty white face, throat, neck ring, and imderparts and the 

 grey above is suffused with more or less brownish. It is, however, always considerably 

 darker than corresponding plumages of other species. This fact and its small size should 

 be sufficient to differentiate it at all times. 



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. 



SUBSPECIES. The Black Tern occurs in both Europe and America in aUied sub- 

 specific forms of which the European is the type. The American Black Tern H.n. sur- 

 inamensis is the only subspecies with which we are concerned. 



This is a bird of the inland marshes. It is rarely seen on the larger 

 bodies of water, but within its regular range no extensive expanse of 

 watery marsh is without it. Its general habits are much like those of the 

 other Terns. 



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 probably retains some insectivorous 

 habits with us. Therefore, we can 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. 



Order — Tubinares. Tube-nosed Swimmers. 



General Description. Tireless fliers of the deep sea, of various sizes from the large 

 Albatross to the small Petrel. Usually dull and evenly coloured birds. 



Distinctions. Nostrils are encased in tubes laid on top of the bill proper (Figure 10, 

 p. 19). 



Field Marks. General flight habits and coloration. Familiarity with the various 

 species is necessary to recognize members of the order. 



Nesting. On ground or in burrows in out-of-the-way localities, often on rocky islets 

 far out at sea to which they find their way in some mysterious manner that we cannot as 

 yet explain. 



'See footnote, p. S4. 



