Tern
2 of the 6 encyclopedias on this shelf carry an entry for Tern. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a family of aquatic birds allied to the gull. The tern is a swifter bird and is often called a sea swallow. In flight the bill of the tern points downward; that of the gull straight forward. The tern darts down to the surface of the water, even diving for its food, and regains wing again. The black tern is ten inches long, with head, feet, and under parts black--upper parts slate color, and under part of tail white. It is an inland bird. It breeds from Kansas and Illinois to Alaska. This tern pays no attention to fish, but skims the swamps on tireless wing, taking insects, particularly the dragon fly . The western plowman is followed by a hovering flock of these fearless birds watching for freshly upturned grubs, which they snatch from the furrow at his very heels. This tern nests in sloughs on floating vegetation, and lays two to three grayish, olive-brown eggs. It goes miles from its nest in search of food.
Collier's New Encyclopedia (1921)
in ornithology the popular name of any species of the genus Sterna. They are slenderly built birds, with long, narrow, sharp-pointed wings, and forked tail, from which, as well as from their swift and circling manner of flight, they are often called sea swallows. The thick, soft, close plumage is colored light blue, black, and white, varying but little with sex, age, or season of the year. They are extensively distributed, inhabiting every zone, but prefer warm and temperate climates to the colder regions, which they only visit for a short period during the year. All are exceedingly active, and from sunrise to sunset on the wing. They walk badly and are not good swimmers, so that they are tossed about like corks. They feed on small fish and marine animals.
What Has Changed in the Last Century
Collier's put every tern in the single genus Sterna in 1921; DNA and anatomical work since the 1990s has split them among a dozen genera, so the black tern described by Aiton's in 1910 is now Chlidonias niger and the common tern alone keeps the name Sterna hirundo. The biggest surprise is the Arctic tern: tiny geolocators fitted to birds and reported in 2010 showed round trips between Greenland and Antarctic waters of roughly 70,000 kilometres a year, the longest migration known in any animal. Legal protection also arrived just after these accounts were written, with the 1918 Migratory Bird Treaty Act ending the millinery trade that had stripped American tern colonies for hat feathers. Aiton's cheerful picture of black terns following the western plowman is now a scarcer sight, the species having declined steeply with the draining of prairie sloughs.
Written for this edition, 2026.