256 
COMMON TERN. 
Sterna Hirundo, Linn . 
PLATE CCCCXXXIIL— Adult Male. 
Although the Prince of Musignano has thought that the bird named the 
Common Tern in America differs from that bearing the same name ’in 
Europe, and has in consequence changed its appellation to that of Wilson’s 
Tern, I am of opinion that no difference exists between the Common Terns 
of the two Continents. The cry of both is besides precisely similar, so that 
with me there is no doubt whatever as to their identity. Experience has 
shewn me that the markings or white spots on the primary quills of Gulls, 
at one time assumed as a criterion by which species might be distinguished, 
cannot in the least be depended on, varying, as they always do, in individuals 
of the same species, at almost each successive moult. Then why, reader, 
should not Terns exhibit analogous changes ? The fact is, they do so ; and 
it is almost impossible, on closely inspecting a dozen or more specimens pro- 
cured at the same period, in either country, to find two individuals exactly 
corresponding in every particular. Some have the bill almost entirely black, 
while others have it more or less red and black, and tipped with yellow. 
The length of the tail-feathers, that of the tarsus, and the size of the inter- 
digital membranes, are all found to differ in some degree, if minutely com- 
pared. If species are to be founded on such slight differences,- an ample 
field is open to those who are ambitious of being discoverers. At all events, 
I cannot help remarking here that it seems to me improper to impose new 
names on objects, until it is proved by undeniable facts that they present 
permanent differences. 
I have observed this species along the Atlantic coast ,of North America, 
from Galveston Island in Texas to the Straits of Belle Isle on the coast of 
Labrador, both in spring and in early autumn. But when on the islands in 
Galveston Bay, in the month of April, I saw only a few arriving therefrom 
the west ; whereas, in the beginning of May great numbers arrived there 
from the east, settled at once, and commenced breeding. I felt convinced 
that the numbers which came from the direction of the Floridas were much 
greater than those which arrived from the westward, and judged it probable 
that vast numbers had at the same time left the Peninsula on their way 
