In 1851, Brooklyn released 100 house sparrows from England; 175 years later, the birds are found across nearly all of North America

A bird that now seems almost impossible to escape once began as a deliberate introduction in Brooklyn. In 1851, about 100 House Sparrows were reportedly released after being brought from England, with the hope that they would help control caterpillars and protect trees.

The plan worked in a way no one could have fully anticipated.