English Sparrow — Invasive Species
Invasive exotic species are those introduced species which benefit from their new environment such
that they increase their population range significantly over time. Invasive species are currently recognized
as one of the main threats to global biodiversity.
English Sparrows, also called House Sparrows, were introduced to North America in the 19th century.
They are now permanent residents found across the United States and Canada, almost always near
areas of human habitation and disturbance or areas with a reliable food source, such as barns or
granaries. They nest in structures ranging from gutters and downspouts to thick shrubs and bushes,
but readily use nest boxes when available. They outcompete native cavity-nesting birds, and are
known to destroy nests and eggs, and kill nestlings and adults while taking over an occupied nest site.
English Sparrows, also called House Sparrows, outcompete native cavity-nesting birds, and are
known to destroy nests and eggs — especially those of Bluebirds and Tree Swallows.
English Sparrows aren’t related to other North American sparrows, and they’re differently shaped. House
Sparrows are chunkier, fuller in the chest, with a larger, rounded head, shorter tail, and stouter bill than
most American sparrows.
Male English Sparrows are brightly colored birds with gray heads, white cheeks, a black bib, and rufous
neck — although in cities you may see some that are dull and grubby. Females are a plain
buffy-brown overall with dingy gray-brown underparts. Their backs are noticeably striped with buff, black,
English Sparrows are noisy sparrows that flutter down from eaves and fencerows to hop and peck at crumbs
or birdseed. Look for them flying in and out of nest holes hidden behind shop signs or in traffic lights, or
hanging around parking lots waiting for crumbs and picking insects off car grills.
English Sparrows have lived around humans for centuries. Look for them on city streets, taking handouts
in parks and zoos, or cheeping from a perch on your roof or trees in your yard. English Sparrows are absent
from undisturbed forests and grasslands, but they’re common in countryside around farmsteads.
English Sparrows eat mostly grains and seeds, as well as livestock feed and, in cities, discarded food.
Among the crops they eat are corn, oats, wheat, and sorghum. Wild foods include ragweed, crabgrass and
other grasses, and buckwheat. English Sparrows readily eat birdseed including millet, milo, and sunflower
seeds. Urban birds readily eat commercial bird seed. In summer, English Sparrows eat insects and feed them
to their young. They catch insects in the air, by pouncing on them, or by following lawnmowers or visiting
lights at dusk.
English Sparrows nest in holes of buildings and other structures such as streetlights, gas-station roofs,
signs, and the overhanging fixtures that hold traffic lights. They sometimes build nests in vines climbing
the walls of buildings. English Sparrows are strong competitors for nest boxes, too, at times displacing
the species the nest box was intended for, such as Bluebirds and Tree Swallows.
English Sparrow nests are made of coarse dried vegetation, often stuffed into the hole until it’s nearly
filled. The birds then use finer material, including feathers, string, and paper, for the lining. English Sparrows
sometimes build nests next to each other, and these neighboring nests can share walls. English Sparrows
often reuse their nests.
For the reasons outlined above, you should not allow English Sparrows to breed in your nest boxes.
There are measures that you can take to prevent them from breeding in your boxes. Unfortunately,
a completely sparrow-proof nest box does not exist. There are several styles that seem to deter the
sparrows for a while, but ultimately if these birds are desperate, they will eventually use the box.
The most successful method for preventing exotic species from breeding in your nest boxes is simply
to move your boxes. Only place your boxes in areas that do not have these birds. English Sparrows
prefer to be near human habitations, and starlings also frequently inhabit agricultural areas with
abundant grain. Therefore, placing your nest boxes in natural areas away from densely-populated
locations will prevent many non-target birds from ever finding them.
Another simple way to reduce the number of English Sparrows around your property is to avoid feeding
them. English Sparrows prefer smaller seeds like millet, cracked corn, and milo, which are plentiful in
inexpensive bird seed mixes. European Starlings, on the other hand, like premium black-oil sunflower
seeds. Bird enthusiasts must accept that wherever there is abundant food, so too will there be
English Sparrows. If you do feed wild birds, offer foods that these species do not appreciate, such
as safflower for Northern Cardinals, niger or “thistle” seeds for finches, and nectar for hummingbirds.
Avoid putting out mealworms and suet, and scattering seed on the ground. Feeders with short perches
and small ports are also less attractive to these two species.
English Sparrows can fit through entrance holes as small as 1 1/4”, therefore most cavity-nesting songbirds
using nest boxes are vulnerable to English Sparrow competition. There currently is no scientifically-documented
way to exclude English Sparrows that works permanently, but some monitors have observed that
Gilbertson PVC boxes are often avoided by English Sparrows. Your best bet may be to use a more active
method of managing English Sparrows. If you prefer, you may alternatively choose to offer only boxes that
are not as vulnerable to exotics (e.g., chickadee boxes, Chimney Swift Towers, or nesting platforms).
Another way to deter the aggressors from nesting is to put up nesting boxes they don’t like such as the
Hughes Slot box. English Sparrows prefer a deep box because they build the dome. A shallow box
prevents them from building the dome and the slot gives native birds an escape.
Because English Sparrows do not migrate, they have a competitive advantage when it comes to having
first pick of suitable nest boxes. By waiting to open your nest boxes until migratory birds return, you can
ensure that they have a better chance of finding an unoccupied site. Simply plug the entrance hole of your
boxes until nesting season begins. Note that this means that your resident chickadees, titmice, and
nuthatches may also have to wait for the migrants to return.
Because English Sparrows are exotic species, they are not protected by the Migratory Bird Treaty Act.
Therefore nest box monitors are legally allowed to remove or harass them. Below we list some humane,
legal actions for controlling or deterring them.
Here are several strategies you may wish to consider:
Nest Removal: When they begin nesting, remove nesting materials every few days.
Incubation Fake-out: Trick the birds into incubating eggs that will never hatch by replacing their
eggs with wooden eggs.
Trapping: Where populations of exotic species are high, trapping may be the only effective
means of managing invasive species. Here are reviews of English Sparrow Traps.
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