Do No Evil
House Sparrows — those little brown birds you see and hear everywhere in our city — are not native to this area. In fact they are not even native to North America.
In the second half of the nineteenth century, some misguided do-gooders began releasing House Sparrows by the thousands in cities and rural environs in the eastern United States.
The do-gooders thought the birds would help control pests. What they did not know was that the introduction of House Sparrows into North America would turn into one of the greatest ecological disasters of modern history and that the birds themselves would become one of the worst pests of all.
With few natural predators to stop them, the Passer domesticus pestilence spread quickly across the continent.
In 1898 it crossed the mountains and reached the U.S. west coast. Further north, it crossed the international boundary and reached deep into Alberta for the first time.
Today, barely 150 years since the first large-scale releases, the House Sparrow has become one of the most abundant songbirds (and pests) on the continent.
The economic damage they cause to humans is well documented. Crops are eaten in the fields and polluted by their droppings in the granaries. Their bulky, highly flammable nests create hidden fire hazards in the walls of poorly maintained buildings.
House Sparrows are a factor in the dissemination of many diseases including tuberculosis, salmonellosis and transmissible gastroenteritis.
Yet every spring, North American gardening stores sell millions of bird houses and nesting boxes perfectly suited to helping this pest species thrive in every city on the continent.
Gardeners today, however, are getting wise about this and other ecological issues. They understand that the success of invading House Sparrows is causing a massive decline in important native bird species such as our own Mountain Bluebird.
Wise gardeners know that bird houses must be carefully selected (openings must be no larger than 1 1/8 inches) in order to avoid creating friendly nesting opportunities for House Sparrows.
Some even take the extra step of monitoring their birdhouses and carefully disposing any eggs or materials left behind by the infamous pest.
They also take care when buying bird feeders to avoid those types that are attractive to House Sparrows. As a result, upside down finch feeders are now one of the hottest selling bird feeding gadgets in North America.
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Brent Johner has been writing about urban wildlife since 1998. Many of the articles here first appeared in the Calgary Herald, Calgary Gardening magazine or on Talk About Wildlife. Brent has also done dozens of radio, television, newspaper and magazine interviews on the subject of urban wildlife.