“Turn” likely describes the way turtles orient themselves, toward warmth, toward water, toward a nesting beach, moving as if guided by the same quiet pull. It’s a fitting word once you learn just how literally turtles do this: sea turtles are famous for natal homing, returning as adults to nest on the very same beach, sometimes the same short stretch of sand, where they themselves hatched decades earlier.
How they manage this is remarkable. Sea turtles are believed to imprint on the unique magnetic signature of their birth beach as hatchlings, then use Earth’s magnetic field like an internal compass to navigate thousands of miles of open ocean back to that exact coastline years later to lay their own eggs. A “turn” of turtles converging on a nesting beach is, in a very real sense, generations turning back toward home.
Freshwater turtles show a gentler version of the same instinct, reliably turning toward the same basking logs, feeding areas, and overwintering spots season after season.
Example: “Every spring, the same turn of turtles returns to nest on this stretch of beach.”
Related: Collective Nouns for Reptiles · What Is a Group of Turtles Called?