The English Sparrow
The first English sparrow was brought to the United States in 1850, but
it was not until 1870 that the species can be said to have firmly
established itself. Since then it has taken possession of the country.
Its fecundity is amazing. In the latitude of New York and southward it
hatches, as a rule, five or six broods in a season, with from four to
six young in a brood. Assuming the average annual product of a pair to
be twenty-four young, of which half are females and half males, and
assuming further, for the sake of computation, that all live, together
with their offspring, it will be seen that in ten years the progeny of a
single pair would be 275,716,983,698.