Science: City Bird

The year 1950, midpoint of the century, is also the 100th anniversary of the landing of the English sparrows in the U.S. Finicky ornithologists regard the immigrants as neither sparrows nor even especially English. They are weaver finches, originally from Africa, and have made a great success in life by attaching themselves, like the dog, the bedbug and the rat, to the fortunes of man. They colonized Europe long ago, swarming in its cities paved with nutritious refuse. In 1850 they reached Brooklyn.

Like other U.S. cities, Brooklyn in those days was plagued by bugs. The shy and decorative native birds...