The mimic that taught Darwin species might not stay fixed
Mockingbirds are New World Mimidae songbirds famed for copying other birds, insects, and frogs in loud rapid strings, and for fierce nest defence. Studies show some species even recognise individual people and adjust threat responses. The northern mockingbird alone is common across North America—and sings past midnight.
About seventeen species sit in two genera today. Three Galápagos forms—including the Floreana or Charles mockingbird and the San Cristóbal mockingbird—once held a third genus, Nesomimus, but now rest in Mimus beside mainland relatives such as the long-tailed, Patagonian, and chalk-browed mockingbirds. Melanotis, which includes the blue-and-white mockingbird, allies more closely with catbirds, while Mimus sits nearer thrashers such as the sage thrasher. The group is therefore not monophyletic. They take an opportunistic omnivore diet—insects, fruit, seeds, and occasional greens—and stake hard territories while raising hatchlings.
When HMS Beagle touched the Galápagos in September–October 1835, Charles Darwin noticed island-to-island differences in Mimus thenca and their kinship to mainland South American mockingbirds. Nearly a year later, writing up notes on the voyage home, he first recorded doubts that species were immutable, linking those birds with what he had heard about Galápagos tortoises. That spark fed his later conviction about the transmutation of species and evolution—an early crack in the doctrine of fixed kinds.
Civic symbolism followed much later. In 1920 the Texas Federation of Women’s Clubs pushed for a state bird; Governor Dan Moody approved the northern mockingbird in January 1927, making Texas the first U.S. state to name one. Arkansas, Florida, Mississippi, and Tennessee later chose the same species—five states in all. Night singing remains part of their reputation, a soundtrack that outlasts midnight wherever the northern mockingbird holds a yard or thicket.
Source: Mockingbird
