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FAQ'S on
Bluebirds' Competitors
What is that brown bird trying to take over my Bluebird box?
How can I discourage House Sparrows (HOSPS) from coming into my yard?
How can I keep House Sparrows (HOSPS) from taking over the Bluebird boxes?
How can I trap House Sparrows?
When should I start trapping
Sparrows?
What should I do with the House Sparrows that I have trapped?
What is a "Sparrow Spooker"?
When do I put up the Sparrow Spooker?
I’ve heard of using Fishing Line to discourage House Sparrows. Does this work, and how do you do it?
What
other birds compete with Bluebirds for nesting sites?
What is that brown bird trying to take over my Bluebird box?
It is quite possible that you are seeing a House Sparrow, a/k/a English Sparrow or HOSP, the Bluebird’s main competitor.
If the bird does not look like the one pictured below, you may be seeing a
House
Wren.
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Male house sparrow, side view |
Male house sparrow, front view |
Female house sparrow |
House Sparrow eggs, nest |
The HOSP is a non-native species
introduced to this country in the mid-1800 with the mistaken idea that it would
help control insect pests. Instead, the HOSP population quickly exploded, and
the birds started destroying the very crops and fruit trees it was thought they
would protect from insects! In addition, the birds started taking over the
nesting sites of the native cavity-nesting birds, causing a dramatic drop in the
population of native birds, most notably the Bluebird. The House Sparrow is
prolific and ruthless. It will destroy Bluebird eggs, incubating adults, and
nestlings, sometimes building its own nest right on top of the bodies of its
victims. See the article
Nothing But Trouble by Ed Nied for an extensive discussion of the House
Sparrow problem.
How can I discourage House Sparrows (HOSPS) from coming into my yard?
Passive House sparrow management consists of discouraging House Sparrows from feeding and nesting in your yard. This can be done in a number of ways.
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Nestbox placement – House Sparrows like to nest in close proximity to humans.
Avoid placing boxes too close to human habitation. Nestboxes in cities or thickly settled areas will likely be claimed by House Sparrows. Avoid placing boxes near the HOSPS’ natural feeding areas such as barns, silos, grain bins, etc. Nestboxes placed closer than 5 feet to the ground may be avoided by HOSPS, but this method should NEVER be used where there is any risk of predation by cats, raccoons or other climbing predators. |
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Plugging the nestbox entrance hole – If a HOSP has already claimed a nestbox, plugging the entrance hole will prevent it from entering and building a nest. It will not prevent it from looking for another nestbox to claim. Some people plug the entrances to their nestboxes after the last Bluebird nesting to prevent HOSPS from roosting in the box through the winter and then claiming it in early spring.
Another option is leaving a box open for one week in the hopes that the HOSP
will abandon it. |
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Use of PVC (Gilbertson’s) nestboxes. This is not a certain method, since HOSPS will nest in PVC boxes, but they don’t seem to prefer them. If you are trying to attract Bluebirds in an area where HOSPS are known to be a problem, you might try starting with a PVC nestbox
instead of a wooden one. However, be aware that HOSPS will enter the Gilbertson’s box to attack the Bluebird nest, even though they may not prefer to nest in the box themselves. |
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Discouraging HOSPS from feeding on your property. HOSPS love “junk food”! They like the cheap birdseed mixes that contain a high percentage of milo, millet, and cracked corn. Feeding only good Black Oil sunflower and thistle seed may discourage HOSPS from visiting your feeders,
and keep them from overwhelming native birds, resulting in more diversity at
your feeder. However, HOSPs will eat sunflower seed, so this is not a sure preventive. Never throw out breadcrumbs, donuts, pastries, etc. if you are inviting Bluebirds to nest in your yard. This will only invite their fiercest competitors into close proximity. Some people have also found success with using devices such as the Magic Halo to discourage HOSPS from feeding on their property. |
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Another method that has been suggested and tried by some
Bluebird landlords can be read about here:
Wing-trimming HOSPs by Fawzi Imad. There has been some success
reported with this method. However, the HOSP's feathers will regrow, and they will still be
able to nest in low pines. |
How can I keep House Sparrows (HOSPS) from taking over the Bluebird boxes?
The only effective solution to a HOSP invasion is to trap and permanently remove the HOSP from its territory. Giving the HOSP “a nestbox of its own” will NOT work. It will try to take over both nests, and
is not likely to leave the Bluebirds to nest in peace. Because HOSP will nest in
close proximity to other HOSP, it is not possible to saturate an area with
enough boxes so other species can safely nest. Quoting from the North American Bluebird Society’s website: “Since House Sparrows are classified as pests and are not protected by federal law, they should be quickly and humanely dispatched as soon as they are captured.”
This is what is referred to as "active" sparrow management. There are passive
methods of control, described above, which basically amount to discouragement
tactics. These may suffice in some instances, but be aware that just ONE
determined male House Sparrow can destroy a Bluebird nest, killing the babies
and perhaps the adults, in a matter of minutes.
It is understandable that many people have strong feelings
about harming a living creature. Bird lovers especially have a difficult time
with the concept of the necessity for House Sparrow control. Since you are
reading this forum, we assume you are a bird lover. However, please understand
that many other Bluebird lovers have struggled with this issue before you, and
have found that where House Sparrows are abundant, the only truly effective
solution that protects the Bluebird is trapping and removal. The trapping and
disposal of this non-native invasive species has a long history.
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Several
articles from Illinois and Indiana newspapers from 1891 and 1892
highlight the problem House Sparrows were causing to native songbirds
even back then. The advertisement below was from the June 1929 issue of
Better Homes and Gardens magazine. (click thumbnails to see larger
versions with readable print) |
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Therefore, BEFORE purchasing, mounting and installing a nestbox, you MUST determine whether or not you are willing and able to practice
active HOSP control if it should become necessary. If not, then as much as you may love Bluebirds, you should not undertake the responsibility of inviting them onto your property by installing Bluebird housing.
It is better to have no box at all than to allow House Sparrows to reproduce in
one. You would help the Bluebirds more by making contributions to the national or state Bluebird societies, or helping to educate those in your neighborhood about proper Bluebird landlordship.
How can I trap House Sparrows?
There are two basic types of sparrow traps: Nestbox traps and ground traps. Nestbox traps are useful for trapping a single sparrow or sparrow pair that have already claimed a nestbox.
Nestbox traps are available for all types of nestboxes:
Universal Van
Ert Trap
Van Ert PVC
Nestbox Trap
Instructions for making the Huber trap
Instructions for making the Bolt Trap
Peterson nestbox traps from Ahlgren Construction, 1289 Otchipwe
Ave. North, Stillwater MN 55082. Cost is $5.50 per trap plus $3 S&H - add $1
more for each additional trap
Gilbertson’s box traps from Steve Gilbertson, HC 5 Box 31, Atkin,
MN 56431, (218) 927-1953. Cost is $6/trap plus $1 S&H.
Ground traps are useful for
trapping large numbers of sparrows in areas where they are numerous. There are a
number of sparrow traps available on the market
Blaine Johnson's Deluxe Repeating Sparrow Trap
- this trap is a new design, and many Bluebirders are very impressed with
its features. Reports from many of our visitors have indicated that the trap
is virtually escape-proof, which is important since a House Sparrow that has
been trapped and has escaped is often very difficult to trap a second time!
(This trap also works very well on trapping Starlings).
Cedar Valley Ground Trap
PMCA Repeating
Trap
When should I
start trapping sparrows?
In-box trapping is best done at the beginning of nesting
season, when House Sparrows are trying to claim a particular nestbox. Ground
trapping, however can and should be done year-round for
greatest success in HOSP control. The NABS (North American Bluebird
Society) flyer House Sparrow Control states: "Used continuously once
the population is under control, its effectiveness, though varied throughout
the course of the year, is usually consistent. These traps are
especially effective during the winter, and when juvenile birds are
abundant in mid summer.
If you use a trap, please be sure to follow these precautions:
If using a nestbox trap, the most likely hours to find the male are between 10 am and Noon. This is the time the male usually gives the female a break from incubation duties.
Never leave any set trap unattended for any length of time, in case a native sparrow or other songbird becomes trapped. If left unattended, the bird could die.
Nestbox traps should be checked hourly, and ground traps at least twice a day.
Ground traps should have food and water (you use the food/wager containers
available for caged birds.) Native birds must be released immediately. The male House Sparrow is very easy to identify, but the females are quite similar to some species of native sparrows. Check a bird book if necessary.
What should I do with the House Sparrows that I have trapped?
There are a number of websites that offer suggestions and solutions on dispatching HOSPS. Or you may wish to purchase a revised version of the Booklet “How to Control House Sparrows”, by Don Grussing.
What is a "Sparrow Spooker"?
A sparrow spooker is a
device that has proven to be an extremely effective house sparrow deterrent when
attached to a Bluebird nestbox after egg-laying has commenced. It is impossible
for a Bluebirder to watch a nestbox 24 hours a day, but a sparrow spooker is on
duty full-time, from first egg-laying to fledging day. Bluebirders have
recognized the life-saving value of sparrow spookers, and some have been constructing
makeshift Spookers for the past 22 years. Many variations on the original design
have been tried, but the basic premise is always the same - shiny, fluttering
streamers suspended above the nestbox discourage House Sparrows from entering
the box, but when installed after the Bluebirds are committed to a nesting
site (once the first egg is laid) they don't deter Bluebirds at all. (Click on
the thumbnails below for enlarged versions of the photos.)
Sparrow spookers can be readily home made, but it is a bit
tricky to put the pieces together, get the horizontal pieces at the right
height, and keep the mylar from coming off. It can also require some
manuevering to mount them so they don't fall over, and so the mylar brushes the
roof top like it's supposed to. In addition, home made ones tend to not weather
well. Finally, some folks just aren't handy, and wanted a ready-made spooker
that could quickly and easily be mounted on any box style "chosen" by a
bluebird. But because of the difficulty involved in creating a design that would
be suitable for many different nestboxes and a variety of nestbox mounting
solutions, there has not been a commercial version of the Sparrow Spooker
available. I even tried to interest one popular manufacturer of bird control
products in the idea of producing a commercial version - without success.
This year some of the
Bluebird Nut Cafe
forum members approached Blaine Johnson, maker of the Deluxe Repeating
Sparrow Trap, to ask if he might be able to come up with a design that
would be adaptable to many different nestboxes and a variety of mounting
configurations. Working along with us, he came up with a version of the
Spooker that allows for almost infinite adjustability, making one design
suitable for use on a wide variety of nestbox styles - from standard boxes
to Peterson and Gilbertson boxes - and also offers quick and easy
installation no matter what method has been used to mount the nestbox to a
mounting post.
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Pictured
at left is Blaine Johnson's Universal Sparrow Spooker, available at
his Sparrowtraps.net website. Not only is this design almost
infinitely adjustable, the spooker is far more attractive and durable
than most homemade designs. |
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A
classic design made with dowels and mylar cut from shiny mylar banners
or balloons. |
A variation made
with a wooden support made of scrap lumber, with a length of PVC pipe
attached to the vertical support with a PVC elbow. The vertical
support is attached to the nestbox mounting post (which in this case
extends above the nestbox itself) with self-locking cable ties.
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Another design, adapted
for use on a PVC nestbox, made with scraps of wooden molding, a copper
plumber's elbow, mylar streamers cut from a foil potato chip bag, and
duct-taped to the horizontal extension.
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Here's
the PVC horizontal extension mounted onto a PVC mounting post with a
PVC elbow. Streamers are again made from a foil potato chip bag and
duct-taped to the horizontal pipe. |
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Another design |
The
great variety of designs demonstrates that the important thing is, not
exactly how you fashion your spooker, but that you begin using one as
soon as the first egg is laid whenever House Sparrows are present in
your vicinity. |
Due to a number of reports of Sparrow kills in TRES
boxes in 2004, some experimentation has been done for the past three
nesting seasons with using Sparrow Spookers on nestboxes where Tree Swallow
were nesting. Evidence suggests that Tree Swallows will also accept
Spookers. We'd like to hear from anyone else who has used Spookers on Tree
Swallow nestboxes. Visit our "Contact" page
and send us a message.
When do I put up the Sparrow Spooker?
Not until after the first egg is laid.
The Bluebird may seem reluctant to enter the box when it first sees the
Spooker, but it usually takes only a few minutes before it gets up its
courage to enter the box. It is best to install the Spooker when you have a
little time to monitor activity at the nestbox. Watch to make sure the
Bluebirds accept it. During egg-laying, the female is not in the nest all
day, so it isn't critical for her to accept the Spooker instantly. The best
time of day to put the Spooker on is right after that day's egg has been
laid, usually in the morning. Then the female has all day to get used to it
before she must enter the nestbox to lay the egg on the next day.
Take
the Spooker down as soon as the babies have fledged, at the same time you clean out the nestbox. You will want to put it back up again for a second or third nesting, again, after the first egg of the clutch is laid.
I’ve heard of using Fishing Line to discourage House Sparrows. Does this work, and how do you do it?
Some people have reported success with using a monofilament HOSP deterrent. It must be done carefully. Monofilament HOSP Deterrent plans
What
other birds compete with Bluebirds for nestboxes?
Please consult the chart below for a number of common cavity nesters. Click
on the thumbnails for larger versions of the photos.
| European Starling (EUST)
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The
European Starling (EUST) is a formidable competitor to Bluebirds in the
wild; however a man-made nestbox with a 1 1/2" opening will not admit a
Starling.
Starlings may still compete with the Bluebird at the mealworm feeder.
Several styles of feeders have been designed to discourage the Starling from
entering. Please see the
FAQ's on Feeding Bluebirds for further information. |
Cowbird
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Male
(Photo courtesy
Carol Johnson) |
Female
(Photo courtesy
Carol Johnson) |
Hatchling
and broken Cowbird egg in Carolina Wren nest
(Photo courtesy Keith Kridler) |
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Cowbird egg in Chipping Sparrow Nest
(Copyrighted Photo courtesy
Chipper Woods Observatory) |
Photos
depicting variations in color of Cowbird eggs |
(Photos
courtesy Keith Kridler) |
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The
Cowbird is what is known as a parasitic nester. It builds no nest of its
own, but lays its eggs in the nests of other species, then leaves the
incubation, feeding and care of its young to the host bird. Often the
Cowbird will remove one of the hosts eggs from the nest prior to laying its
own.
If a Cowbird lays an egg in a Bluebird nest, the Bluebirds may raise the Cowbird young at the expense of their
own chicks. Check your State regulations regarding the legality of removing
a Cowbird egg from a Bluebird nest.
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House Wren
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House Wren Egg |
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House Wren nest |

Bluebird Egg with holes
typical of
pecking by House Wren
(Photo courtesy Michelle Sharron) |
(Photos courtesy Leslie McCulloch, Bet
Zimmerman) |
A small, brown, native bird with a beautiful song.
The House Wren can be a problem for Bluebirds, as it frequently fills several desirable nesting sites with twigs,
but only uses one nest. It has also been known to enter nestboxes where
Bluebirds are nesting, pecking holes in the Bluebird eggs. Being a native songbird,
however, it is a protected
species, and its completed nest and/or eggs should never be disturbed. It is
possible to discourage a House Wren from building in a
specific Bluebird nestbox before the nest is complete by
repeatedly emptying the box of the twigs that the House wren deposits there . But
the best defense against House Wrens is to place the Bluebirds nestbox in a
fairly open location, at least 100 feet from densely wooded areas, as the House Wren
prefers to nest in or near wooded land.
Some success has been reported with the use of "Wren Guards" on
nestboxes. See
Bob
Orthwein's 1996 report on Wren Guards.
For more information on House Wrens, see
http://www.sialis.org/wrens.htm
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| Tufted Titmouse

(Photos courtesy Pam Spielmann, and Crystal Hill) |
The Titmouse
(TUTI) is a native cavity nester and a very desirable nextbox tenant. They
may nest in Bluebird boxes, but they are able to use boxes with smaller
openings. If you have Titmice and Bluebirds competing for a nestbox, the
Bluebirds will frequently win because they are the larger bird. Often the
best solution is to provide a second box, and place a hole reducer on the box the
Titmice prefer to prevent
the Bluebirds from interfering with their nesting. Traditionally, hole
reducers are placed on Titmice nests after the eggs are laid, but in some
cases, they have been successfully added prior to egg-laying in cases of
severe harassment by Bluebirds. |
| Black-Capped Chickadee

(Photos courtesy Wendell Long, Janie Hoffman) |
Chickadees, like Titmice, are very desirable nestbox tenants. (See above) |
| Tree Swallow (TRES)

(Photo courtesy of Wendell Long)
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The Tree Swallow (TRES) is a beautiful bird
welcomed by many Bluebird nestbox owners. If you have both TRES and
Bluebirds, you are doubly blessed! The two species can often be encouraged
to nest in close proximity by providing nestboxes in pairs, placed 5 -
25 feet apart. The TRES have just one nesting per season, so often a
Bluebird will choose a TRES nestbox for its second or third nesting of the
year. TRES feed by catching insects in the air, and Bluebirds are ground
feeders, so they are not competitors for the same food sources. |
| Carolina Wren

(Photos courtesy Leah Solliday, Bet Zimmerman) |
Not
known to be aggressive toward Bluebirds |
Bewick's Wrens
(Photos courtesy Shelly Harris) |
Not known to be aggressive toward Bluebirds. |
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More FAQ's:
Bluebird
Housing
Nesting Habits
Feeding
Predators,
Pests, Parasites, Problems
Return to Bluebird Nut Cafe's "Bluebirds 101"
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