The Problem: House Sparrows often take over nest sites of other cavity-nesters,
killing eggs, young, and adults.  















House Sparrows can be a nightmare for people who love Tree Swallows, Bluebirds,
and Purple Martins.  These non-native birds, also called English Sparrows, were
introduced from Europe roughly 150 years ago.  They now number over 80,000,000 in
North America, occurring just about everywhere people live.  And wherever House
Sparrows are found they compete with native cavity-nesting species for nest sites.  
Every year they are directly responsible for the violent deaths by pecking of
thousands of bluebirds, Tree Swallows, Purple Martins, chickadees, and others.  
Photo below by Dick Stauffer of swallow nestlings killed by House Sparrows.
















Although native birds try to defend their nests from destruction and usurpation by
House Sparrows they usually lose in the end.  Photo below by Tom Beattie.

















It is better to have no nest box at all than to allow House Sparrows to breed in one.

You must be able to identify House Sparrows so you can act to prevent injury or
death of your swallows if House Sparrows intrude at their boxes.

Male and female House Sparrows look different (male below left; female below right).  
Please study the photos on this page and/or refer to a field guide if you aren't sure.  
Remember, not all small brownish birds are House Sparrows.













The very best source of information concerning the House Sparrow problem is the
bluebird hobbyist web site Sialis.  Click here for its comprehensive presentation of
issues and tactics of House Sparrow control.  We will not try to restate this material.  
Instead, we will consider two House Sparrow versus Tree Swallow situations:
  • What to do if sparrows are threatening your swallow nests now.
  • How to avoid sparrow destruction of swallow nests in the future.

IF you have Tree Swallows nesting NOW, and House Sparrows have found their box:
  • Odds are the sparrows will not go away, and it's only a matter of time before
    they destroy the swallow nesting.  Your options are limited in this case.  You
    can either kill the House Sparrows or try a "sparrow spooker".
  • House Sparrows are not protected by law.  They can be trapped and killed, or
    killed outright.  Methods for doing this are presented in detail on the Sialis
    page noted above, along with the reasons why trapping and relocating should
    not be done.
  • If you don't want to kill intruding House Sparrows try a "Sparrow Spooker".  
    These are easily made devices that really work according to bluebird experts.  
    Click here for sparrow spooker plans and instructions for use from Sialis.   

IF House Sparrows have destroyed your Tree Swallow nestings IN THE PAST, or you
fear it could happen IN THE FUTURE:
  • You can either rely on the methods mentioned above, or relocate your boxes.
  • We strongly recommend placing swallow boxes far from houses, barns, and
    other buildings where House Sparrows congregate, at least 100 yards away,
    preferably much more.  This is the best way to avoid sparrow competition.
  • Don't add more boxes to "give everyone a chance to nest".  More is not better.





















Slot-Entranced Boxes will NOT solve the Tree Swallow - House Sparrow problem.
Attention!  The narrow-slotted boxes of the type described on this page will NOT
work for bluebirds, because bluebirds are actually larger than House Sparrows.  
There is no bluebird nest box design that House Sparrows cannot and will not enter.

For several years Duncraft sold a swallow nest box featuring a narrow entrance slot,
which was said to "deter House Sparrows".  The idea was that Tree and Violet-green
Swallows, with their slender bodies and small heads could enter easily but the bulkier
House Sparrows could not.  

We tested a Duncraft swallow box for one season.  All we can say is that ours was
ignored by sparrows but quickly accepted by swallows, which nested successfully.  
However, although the Duncraft box slot is only 1" high, cut in 3/4" thick wood, we
have heard reports that some House Sparrows have been able to squeeze through.  
(Duncraft seems to have stopped selling this box in 2011).




















Ryan Hoelke of Canadian Woodwork in Ontario, has experimented with slotted boxes
like the one below, that have slots even narrower than the 1" Duncrafts.  He found
Tree Swallows were unable to pass through 7/8" slots cut in wood 3/4" thick, and
that slots in boards had to be 15/16" or 1" before swallows could enter successfully.  
However, Mr. Hoelke suggested another possible method for excluding House
Sparrows from swallow boxes; "Sparrow Stoppers", similar in principle to the Starling
stoppers used by some Purple Martin enthusiasts.
















"Sparrow Stoppers": a failed experiment.













Sparrow Stoppers are pieces of plastic 1/8" or less thick, with a narrow slot only 7/8"
high and 2-1/4" wide which, when attached over a larger opening in the wood
behind, may exclude House Sparrows, but allow Tree Swallows to enter.  The larger
opening in the wood was felt necessary to give swallows the room they needed to
squirm past the plastic barrier.  





















We had high hopes.  If simple plastic "Sparrow Stoppers" like the one above really
would let Tree Swallows nest unmolested by House Sparrows they could save
thousands of swallow lives every year.  And not just Tree Swallows.  We hoped
Sparrow Stoppers might protect other small cavity-nesters, including Violet-green
Swallows and Chickadees.  Photo below of a Violet-green Swallow by Rob Robinson.















In the spring of 2011 over 150 persons from across the US and Canada tested Sparrow
Stoppers.  We are unhappy to report that the stopper failed to prevent House
Sparrows from entering some of the volunteers' stopper-equipped nest boxes.  

In light of this failure we can only fall back on our recommendation to locate boxes
intended for native songbirds far from buildings whenever possible to reduce the
chance of House Sparrow damage, and hope that some creative person will find a
successful way to thwart sparrows in the future.








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House Sparrow Damage