Originally Posted by
sagegrouse
The legend of the House Finch is worth telling, assuming that the stories I heard years ago are true. It is a Western finch for the drier parts of the country, but it turns out that it really likes to nest on houses and other structures. Part one is that it succeeded living among humans, and its range began to expand in all directions, but mostly eastward.
Part two is that the Migratory Bird Treaty Act of 1918 prohibits the "killing, capturing, selling, trading, and transport" of protected bird species -- basically all species except game birds and alien species like starlings and house sparrows that came from elsewhere. As it turns out, it was a common practice to sell the colorful House Finch in pet stores. Shortly after World War II the Audubon types in New York went around to the pet stores and informed the owners of the law and their almost certain violation of it. The pet store owners did the only reasonable thing (from their point of view) -- they released the birds from their cages. Thus, it turns out, the House Finch became a released bird in the wild in the NYC area. And it thrived! Moreover, it spread rapidly over the years. And -- I understand -- that the eastward moving wild bird species from the American West has now met up with the westward spread of the NYC released birds.