Part II: Malthus & the Sparrow

In Part One of "Malthus & the Sparrow" I recounted how the intensification and mechanization of agricultural in Western Europe was a likely culprit in the precipitous decline of the house sparrow on that continent.

Part II of the story deals with the house sparrow in the U.S. This is a story about an invasive species, about immigrant assimilation, and -- of course -- about habitat destruction caused by increasing levels of human population growth.

Let's start with the invasive species story.

Invasive species are a serious threat to animals and plants across the globe, including right here in the U.S.

America's native fish populations have been decimated by introduced species, and its forests and prairies have fallen victim to alien fungi (chestnut blight, Dutch elm disease, dogwood fungus), beetles (Asian longhorn), caterpillars (gypsy moths), and grasses that have devastated entire eco-systems.

Avian malaria and avian pox in Hawaii managed to push more birds into extinction on those islands than all other actions against all other birds here on the mainland.

And now, of course, the West Nile virus is hammering bird populations across the U.S. and Canada, with the real wave of destruction still ahead when the virus gets to mosquito-rich Mexico and Central America where "our" song birds spend the winter.

That said, most of the plants and animals that have come to our shores have settled in without being terribly "invasive," and many "invasive" species have interesting histories worth knowing.

The gypsy moth, for instance, was brought to the U.S. by a Frenchman that wanted to start a silkworm industry here in the U.S. (don't ask).

The nutria that are eating up the bayous of Louisiana (and which are also found in Maryland and Oregon) were brought to the U.S. by the McIlhenny Tabasco Sauce family and managed to escape after a hurricane decimated their cages on Avery Island.

The starling was brought to the U.S. by someone who wanted to introduce all of the birds of William Shakespeare's sonnets into Central Park.

The house sparrow's story in America is no less interesting.

The house sparrow, (or "English Sparrow" as it is sometimes called) was first introduced to the U.S. in the 1850s and promoted to city officials across the East and Midwest as an effective form of pollution control -- sparrows were supposed to clean up the horse droppings littering America's streets.

Mayors, city councils and park officials heralded the release of sparrow colonies in much the same way they heralded the arrival of gas lights and indoor plumbing -- as a sign of America's coming of age. The house sparrow was, quite literally, a kind of "equine catalytic converter" designed to make our increasingly crowded cities a cleaner place to live.

Within 20 years after its introduction, the booming population of house sparrows in the U.S. was perceived to be having a negative impact on some native song bird populations, especially eastern bluebirds, tufted titmice, and various chickadees.

The friction between the immigrant and native birds was largely due to the aggressive nature of the house sparrow which simply out-competed some native birds for housing and (to a lesser extent) food.

The rise of the house sparrow created one of the more interesting environmental battles of the late 19th and early 20th Century. Dr. Thomas Mayo Brewer -- a great friend of John James Audubon and a co-author of the first modern catalog of American birds -- thought the house sparrow was a wonderful and determined little bird and that, in time, it would prove to be one of America's favorites.

Opposing Dr. Brewer's love of the house sparrow was Dr. Elliott Coues, whose "Key to North American Birds" remains one the most important works of American ornithology. Dr. Coues advocated an open war on house sparrows, saying they were a peril to native birds. Dr. Coues described the house sparrow as "sturdy little foreign vulgarians," and "animated manure machines ... without a redeeming quality."

This fray between naturalists was, believe it or not, a minor cause celebre, and was enjoined by the likes of Harriet Beecher Stowe (on the side of Brewer) and the very young Theodore Roosevelt (on the side of Coues).

In 1883, the American Ornithologists' Union (AOU), a newly formed organization made up of the most eminent men in the field of birding, resolved at their first meeting to decide "the eligibility or ineligibility
of the European House Sparrow in America," i.e., should the sparrow be granted the right to be called a naturalized American bird?

In the end, the AOU concluded that the house sparrow could not be admitted as an American species.

Despite this ruling, the house sparrow eventually made its way into the AOU's "Check List of North American Birds," as an "introduced" species. By 1931 this distinction had evaporated and the house sparrow was added to the AOU check list without any quibbling or further notation.

The house sparrow had, for all intents and purposes, been assimilated and was now a "North American Bird".

At about the same time that the American Ornithologists' Union was removing the asterisk next to the house sparrow's name, house sparrow populations began to decline as automobiles replaced horses in America's streets. Changes in farming practices further reduced the amount of grain spillage and horse manure available for avian gleaning. By the end of the 1940s, the first "house sparrow" reduction had occurred.

A second reduction in house sparrow populations occurred in the 1970s and 1980s. The reason for this reduction was the rise of another bird in the eastern United States: the house finch.

The house finch is native to the American west. A pretty bird (it looks like a sparrow dipped up to its neck in red wine), house finches were live-trapped in California after World War I and sold in eastern pet stores as "Hollywood Finches."

In 1940, however, the sale of domestic-caught wild songbirds was banned in the U.S. Caught with a small inventory of now illegal "Hollywood" finches, a pet store in Long Island simply released them out the back door. From this modest and impromptu introduction sprang the millions of rose-headed finches we now have storming our bird feeders across the East.

The house finch proved to be aggressive enough to "beat back" the house sparrow, and a kind of detente now exists, with each bird helping to hold down the other's population.

What about the birds that were once in decline due to competition with house sparrows? Ironically, they are doing fine and probably exist is numbers larger than they did in pre-Columbian time when the east was entirely in forest. Edge-habitat-loving populations of eastern bluebirds, tufted titmice, and chickadees are back up with the help of thousands of bluebird boxes constructed and placed in parks, on fence posts, and along nature trails by a generation of school children, boy scouts and dedicated birders.

As for Brewer -- the "winning" side of the house sparrow war -- "Brewer's Sparrow" is named after him. Ironically it is a native bird.

A bird is also named for Elliot Coues. Coues' Flycatcher, however, is mostly found in Mexico and Central America and can only be seen in the U.S. in the mountains of Arizona and New Mexico. Adding insult to injury, the AOU recently decided to change the name of Coues' Flycatcher to "Greater Peewee".

Clearly when you lose a war -- even a "sparrow war" -- your immortal monuments do not last for long.