I look out my window, and they’re everywhere: hundreds of house sparrows flit around our shrubs, hop around the yard, and steal food from our backyard chickens.
At this time of year, the males puff up and display, making them appear like much larger birds. They cheep incessantly, often drowning out other birdsong.
Given their constant presence, it seems odd to be writing this: House sparrow populations have been declining worldwide, including in their native range.
House sparrows are often considered one of the most adaptable birds, capable of thriving amongst our farms, suburbs and cities. The real story of their spread and decline is a bit more complex, and may have implications for urban conservation.
The Sparrow Fad
The house sparrow (Passer domesticus) is native to Eurasia, but beginning in the mid-1800s, it spread around the globe. Largely due to intentional releases by humans, house sparrows are now found on every continent except Antarctica, as well as many islands. It is the most widespread wild bird on earth.
As with many aspects of conservation history, many of the details of sparrow introductions are poorly documented. The first introduction to North America was to New York City in 1851 or 1852, although the 8 pairs released seemed to fare poorly. However, this set off a wave of introductions throughout the United States.
For a time, some sources refer to a “sparrow fad,” with private individuals breeding birds, and others catching them and releasing them into new areas. Nest boxes were installed in cities to increase sparrow populations. Ornithologists and others raised concerns over the merits of house sparrows, but their arguments proved futile against sparrow enthusiasts releasing cages full of birds.
The reason for many of these reasons was for pest control. For instance, their 1868 introduction to Philadelphia was apparently an effort to control inchworms. As with so many such pest control efforts, the cure proved worse than the disease. They thrive on a variety of foods, including spilled grain and even garbage.
The house sparrow is also an aggressive little bird. It nests in cavities, and pushed out native species like Eastern bluebirds. Backyard birders who erect birdhouses have undoubtedly noticed house sparrows bullying wrens and other native species.
Public sentiment turned quickly against the house sparrow. By the 1880s, just three decades after the first introduction, several U.S. cities paid bounties for the birds. But by then the bird was firmly established – and spreading.
Recent research published in the Proceedings of the Royal Society B found that house sparrows underwent genetic changes, including modified skull development and a gene that helps create the enzyme amylase that helps break down starch. The researchers hypothesized that these changes helped sparrows adapt to human settlements dominated by agricultural fields and livestock. The sparrows, according to the research, diverged from other Old World sparrows around 11,000 years ago, just as agriculture was taking hold in the Middle East.
The house sparrow appears to be a clear winner in the Anthropocene: an adaptable bird capable of thriving equally well on cities and in farms.
But over the past few decades, ornithologists have noted a new trend: house sparrows are in widespread decline. According to the Cornell Lab of Ornithology, house sparrow numbers in North America have declined by 84 percent since 1966. In Philadelphia, the city where the sparrows were introduced to control inchworms, the birds have largely disappeared.
Many birders view this as a good-news story. After all, house sparrows compete with native species and are generally viewed as a pest. However, the bird is experiencing similar declines in many parts of its native habitat, including the United Kingdom and Western Europe.
In England, house sparrow populations have declined by half. The species is listed by the Royal Society for the Protection of Birds as a species of high conservation concern. While the United Kingdom population has recently stabilized, the bird remains of concern to conservationists. European countries now recognize a World Sparrow Day to raise awareness of the plight of this once-abundant species.
Theories abound as to why house sparrows have declined. The answer likely lies in a combination of factors, all tied to rapid changes in both cities and farms. House sparrows may be highly adaptable, but that doesn’t mean they can thrive with every modification humans make to the environment.
The first house sparrow decline was actually reported in the 1920s, when automobiles began widely replacing horses. Sparrows feasted on the huge amount of spilled grain found in cities. When that food source was removed, sparrow populations decreased.
The Royal Society for the Protection of Birds and others note that changing agricultural practices likely play a significant role in the current sparrow decline. Once, farms were diverse, with crop fields and livestock barns scattered across the landscape. New, clean, intensified monocultures result in less spilled grain, and less cover around fields. In many parts of the world, other birds associated with farmland are also in decline.
Livestock is more frequently raised in confined operations, sometimes even indoors. All this results in fewer opportunities to feed on grain.
Similarly, city sanitary practices have improved, which may make finding meals more difficult for sparrows.
Research published in the journal Frontiers in Ecology and Evolution found that a combination of poor diet and air pollution induced physical stress on house sparrows, leading to reduced reproductive success.
The widely reported global insect decline may also be a significant factor. Many think of house sparrows as vegetarians, gobbling bird seed and grains. But, as with many birds, they rely on protein-rich insects to feed their young.
Implications for Urban Conservation
There are still 540 million house sparrows flying around the planet, so this bird is not in danger of going extinct. It’s still abundant in many places – including my neighborhood, where a mix of native vegetation, bird feeders and backyard chicken coops provide the diversity of habitat and food sources that enables these birds to thrive.
So why is the house sparrow decline important?
In part, it shows how little we understand urban ecology. Even conservationists often assume that common, adaptable species will be able to adapt to any change. That’s clearly not the case.
All ecosystems change, but human environments often change rapidly. If we’re thinking about protecting biodiversity in cities – and in a world that will have 9 billion people, we have to – we have to think about how changes impact wildlife. Just as modification to a tropical forest affects wildlife, so too do changes in farming practices, changes in city design, even changes in bird feeding habits.
I wouldn’t miss the house sparrow from my neighborhood. It’s an invasive species that competes with native birds. But globally, the sparrow’s decline is a story we should heed, as it may help us better understand how to coexist with nature in the Anthropocene.
Join the Discussion
In Reynolds, Indiana the House Sparrows live in the Honeysuckle vines by the house. The biggest danger for them is the Red Tailed Hawk that lives somewhere near my house. We watched the hawk swoop down and pick a sparrow right off the ground. Interesting read !
We have an abundance of them in my yard in Indianapolis, Indiana. We have a lot of House Wrens as well, and the two seem to get along alright.
can we quit calling species, invasive, since they did not invade any where. they were captured and released. they were removed from their native places and brought her for amusement or commerce. anthrocentric language sucks and is not accurate and just promotes more anthrocentrism
Just about every reason listed should impct more than just house sparrows and more than just sparrows.Many bird species are in decline but not all. If the highly adaptable and fairly agressive house sparrow is in decline shold it not be even worse for other sparrows and other birds using the same food and nesting sources? There must be more to this mystery.
I have noticed a huge decline in various bird numbers in recent years. You have not mention the pesticide plague from Dow &Monsanto, to name a few of the chemical giants, destroying our environment & natural world.
Give me spots on my apples. but save me the birds & the bees…..
Totally agree…and pesticides and herbicides use are a consequence of a change in cultural norms and perceptions..probably fostered by the very companies selling us pesticides etc…Most younger than 50 Americans I know are terrified of insects, mice, snakes etc..Their notion of ” nature” is of a carefully sanitized, deodorized, well policed world where only cute poodles, declawed indoor cats and song birds have a place.
Around here they rarely even get outside. The millennials flooding Denver live in boxes without yards or even balconies. lots and lots of people, not much wildlife. The politicians encourage them to come because they want more tax money to spend.
For years the English house sparrows gobbled up almost all the seeds I put out in my feeder. The only birds strong enough to fight them off were the cardinals. Finally, I tried plain safflower seed which apparently is not to their liking and they quit coming to my feeder. Finally other native birds can now feed like purple finches, chick-a- dees and nuthatches. I live in the city but have a decent size yard.
Is there any bird species that likes red amaranth. It volunteers in my garden every year?
When I took an ornithology course at Cornell I was told they were introduced to help clean up the horse manure littering urban streets. But they have done just fine around here in south-central Iowa until this year when I saw very few at the feeders although purple finches and house finches were just as abundant as ever. There has been a great dieback of insects due to increasingly toxic insecticides and that may well be a cause. Honey bees were as scarce as monarchs. Not just monarchs, as people notice, but all species of butterflies and moths and even grasshoppers. There was only one species of sphinx-moth last year, and showy species like swallowtails were very scarce.
Thank you for your article. I live in a large eastern European city. When I moved into my present apartment in 2003, there was still a decent flock of house sparrows living in my immediate surroundings (lots of small yards in the neighborhood – it’s not what you would call an ‘urban jungle’). Then the buildings in my neighborhood began to be winterized, all the nooks and crannies were now inaccessible under a layer of styrofoam insulation and a skim coat of plaster. Then the city started intensively mowing a block-long wide swath of lawn across the street, so the ground cover there could not mature and release its seeds – I wondered how this may have impacted the ability of the birds to forage in winter. And slowly, the population began to disappear. For a few recent years, I heard no house sparrows, only tree sparrows, if any at all. I wish someone here would do more studies on this, because, for example, I was thinking that people in the US have been mowing public spaces and private lawns for years, and it didn’t seem to affect the house sparrow population – at least not in the 1980s, when I was still living there (but perhaps a decline was underway then that we didn’t see). The population seems to be making a small comeback here – last year and this, efforts are being made to set up colonial nest boxes for them (it remains to be seen if they actually use them) and certainly bird feeding in winter has become more popular (it was basically nonexistent when I arrived in 1991). House sparrows are still very common and numerous in rural villages – but as you note, changes in agricultural and livestock practices, especially since accession to the EU, are radically changing the rural landscape. It will be interesting to see what happens over the next few years, and I will try to find some local research on this topic.
I live in Hebron, In. I have sparrows all year long in my yard, a black bird with a white beak, comes to my yard this time of year and goes into the sparrows nests and eats the eggs , kills the babies and destroys the nest, I am hateing this black bird. I have a few red birds and blue jays, wood peckers, wrens and soon the hummers will be here. The blue bird and Orioles pass thru, don’t stay long but I love to see them. I used to have barn swallows , but they seem to be less each year. A few bats, I love to feed the birds, and yes, I have one brown hen and she is the boss when seed feeding time come s in the morning. Oh, and this year I am flooded with 8 baby squirrels. Help, these little demons are funny to watch but very destructive , tree branches all over my yard and u know how they eat all the bird seed?? ??????????
Well. Apparently, our bird feeder and two large arbor vitaes have become a sparrow hotspot. We also have the ring-necked dove, mourning dove, and, just yesterday, a red-headed finch. Last year, we even had a Woodhouse Jay, since our neighbor has a Colorado blue spruce and we planted a burr oak. We love the crazy variety, even entertaining a peregrine falcon one night that I think we perusing our 1/4-acre lot for the other critters we occasionally glimpse, and, probably, the birds. It didn’t seem to score and only stayed for two days. I think I’m glad to be able to answer where the house sparrows have gone. I can safely answer, at least on OM, here. Oh yes, here. Over the few years, since we confined our cats to indoor only, and gave them a cat tree that faces the bird feeder, we have watched a steady increase in our population. Last year, they welcomed a lost parakeet, to my shock. I don’t why they all get along, but they do.
We are in the process of putting in more trees & bushes to accommodate our feathery tenants, but, at this time, they flit between our yellow-rose thicket, arbor vitaes, locust, and acorns. I hope our little ecosystem, in which we allow no pesticides or herbicides, ensure there will be continue to be places for birds, bees, and other critters.