60 MICHIGAN BIRD LIFE. 
Distribution.—North America generally, breeding from Manitoba 
southward to Virginia, Illinois, Texas, and California; in winter southward 
to Brazil. 
According to several writers this should be one of the common terns 
of Michigan, but as a matter of fact, there are remarkably few actual 
records. It was reported by most of the earlier writers to breed commonly 
at St. Clair Flats, and according to Swales (1904), there is little doubt it 
does nest there, although he has never taken it. We have a single specimen 
in the Agricultural College collection which was taken on Long Lake, 
Kalamazoo county, May 24, 1884, by Dr. Gibbs. B. H. Swales has a spec- 
imen taken on the lower Detroit River, Sept. 10,1890, by J. Claire Wood, 
(Auk, XXIV, 1907, 137). In his Birds of Indiana (p. 576) Butler 
states that it is the most common tern on Lake Michigan during 
the fall. In Kumlien & Hollister’s ‘Birds of Wisconsin,” p. 12, it 
is said to be acommon migrant during the first two or three weeks of May 
and again from September until the middle of August; and still later on 
Lake Michigan. There is little doubt that the Detroit and St. Clair rivers 
mark the eastern boundary of the range of this species; while it occurs in 
much greater abundance in the Mississippi Valley. Unlike the Common 
and Arctic Terns this species prefers to nest in marshes instead of on sand 
or gravel, and its nests are often built on floating vegetation or on ridges 
of refuse washed up by the waves. Its eggs are similar to those of the 
Common Tern and equally variable in color and markings. They average 
1.78 by 1.23 inches. 
TECHNICAL DESCRIPTION. 
So similar to the Common Tern in corresponding seasonal dress as to be separated with 
difficulty and then only with specimensin hand. The two species have precisely the same 
measurements except that the tail of Forster’s Tern will average about an inch longer. 
Two points alone can be depended upon for separating them: In Forster’s Tern the breast 
and belly are pure white and the inner web of the outer tail feather is always darker than 
the outer web, which is entirely white. In the Common Tern the breast and belly are 
pearl gray and the outer web of the outer tail feather is dark, while the inner web is white. 
These two differences in coloration are constant summer and winter. In other respects 
winter specimens of these two terns are almost precisely alike and the same may be said 
of the young of the year. 
Length, 14 to 15 inches; wing, 9.50 to 10.30; tail, 5 to 7.70 (forked for 2.30 to 5 inches); 
culmen, 1.50 to 1.65. 
22. Common Tern. Sterna hirundo Linn. (70) 
Synonyms: Sea Swallow, Mackerel Gull, Wilson’s Tern, Lake Erie Gull.—Sterna 
hirundo, Linn., 1758, Wils., 1813, Nutt., 1834, Aud., 1838.—Sterna wilsoni, Bonap., 1838, 
Baird, 1859. 
In full plumage may be distinguished by its red bill with the terminal 
third black, breast and belly light gray, and outer web of outer tail-feather 
dark, the inner web being white. 
Distribution.—Greater part of Northern Hemisphere and Africa. In 
North America chiefly east of the Plains, breeding from the Arctic coast, 
somewhat irregularly, to Florida, Texas, and Arizona; and wintering 
northward to Virginia. Also coast of Lower California. 
The commonest tern in Michigan waters, frequenting the shores and 
islands of the Great Lakes, as well as all the principal streams and interior 
lakes, and likely to appear on any pond or pool during migrations. It is 
absent from our waters only during the severest part of the winter and is 
one of the attractive features of the water about our summer resorts. 
Formerly it was much more numerous than at present, but the craze for 
