Managing House Sparrows

"Without question the most deplorable event in the history of American ornithology was the introduction of the English Sparrow." -W.L. Dawson, The Birds of Ohio, 1903

Warning: This webpage deals with both active and passive means of managing House Sparrow (HOSP) populations.

A male Western Bluebird that was trapped inside a nestbox and killed by a House Sparrow. Photo by Claudia Daigle.

CONTENTS:

• The Problem
• Recognizing a HOSP Attack
• Identification of House Sparrows
  
• Management Choices
  • Passive Control: (discourage birds from nesting)
    • Feeding
    • Magic Halo
    • Nestbox Location
    • Clustering and pairing Nestboxes
    • Nestbox Type
    • Nestbox Color
    • Light
    • Hole Restrictors/Reducers
    • What doesn't work
    • Monofilament (fishing line)
    • Sparrow Spooker
    • Removing Nestboxes altogether
    • Exclusion
    • Plant Management
    • Chemical Repellants
  • Active Control: (interfere with nesting process or HOSP themselves)
    • Increased Aggression/Revenge/Rampage
    • Dealing with a Wary Male
    • Traps
      • Decreasing odds of capturing non-target native birds
      • Removing trapped birds for an inbox or ground trap
      • Trapping in public places
      • Temporary Boxes or Changing Box Height to Enable Trapping
      • Nestbox (Inbox) Traps
      • Remote Controlled Traps (including "fishing")
      • DIY links
      • Ground Traps
        • Decoys
        • Playbacks (recordings)
      • Sticky Mouse Traps
      • Mist nets
    • Wing Trimming
    • Removal of Nests/Eggs
    • Rendering Eggs Infertile (Addling)
    • Guns
    • Electricity
    • Other Methods
  • What Doesn't Work
  • References and Links

Also see: HOSP Photos, History, Attacks (warning: graphic photos), photos and descriptions of other brown birds that look like HOSP, Biology, Population Proliferation, Video Clip of HOSP Attack, information on euthanizing captured birds, HOSP advisory handout for people with boxes used by HOSP and one for commercial facilities allowing HOSP to breed/roost/feed, trap review, and essay "Are HOSP Evil?" Separate webpages with drawings and photos on sparrow spookers, Magic Halo, and How to Trim Wings and Links for more information and DIY drawings. Also see ongoing experiments to deter HOSP and Bluebird Widows/Widowers/Orphans.

If you want to attract bluebirds, you will have to deal with House Sparrows (HOSP) if they are common in your area. HOSP are probably the number one enemy of bluebirds and purple martins. Unlike starlings, they are capable of entering the 1.5" round hole of a nestbox. HOSP have been observed threatening and attacking 70 species of birds that have come into their nesting territory.

You might think they're cute (some bluebirders refer to them as "rats with wings"), but they attack and kill adult bluebirds (warning: graphic photos), sometimes trapping and decapitating them in the nestbox and building their own nest on top of the corpse. They destroy eggs and young. At a minimum, they often harass native birds (especially more timid species like chickadees) into abandoning nestboxes. A HOSP flock near a nestbox can also cause premature fledging. They will also overwhelm bird feeders, driving other species away. (Ben Lincoln reported that 16 HOSP went through 3 lbs. of birdseed over a two day period.)

If you are serious about bluebirding, you should be serious about HOSP control. Do not put up a nestbox if you are unable or unwilling to monitor it and prevent HOSP from nesting.

For those who find it hard to deal with HOSP, here are some accounts of experiences repeated all too often:

• "I pray that you never have to experience the shock of opening a nestbox to find a nest full of babies, mutilated and dying, or on the ground, covered with ants, or broken eggs, or a blood-covered mother bluebird who fatally tried to protect her young.
• "I had bluebird pair nest in my purple martin house. Given 11 other compartments to choose from, the House Sparrows still killed the nestlings."
• "If you ever happen to see a bluebird enter a nestbox, followed by a "Passer domesticus" or House Sparrow, you might experience what I did minutes later--holding a beautiful male bluebird in your hands, bloodied and blinded by the attack, taking his last dying breaths."
• More quotes (Warning: includes graphic photos)

I have heard reports that in some areas HOSP and native cavity nesters appear to peacefully coexist. This may be due to a less aggressive HOSP population. It may also be because HOSP that have not become accustomed to using nestboxes, as they do not require cavities to successfully nest. I wonder whether this situation would change as local HOSP populations increase or when HOSP learn to utilize nestboxes which offer better protection from weather and predators. I often see reports of people who say they have had HOSP for years, and then suddenly start seeing attacks. It is usually just a matter of time.

House Sparrows cause other damage: to crops (esp. grains) and gardens (eating seed, seedlings, buds, flowers, young vegetables [such as peas and lettuce], maturing fruit [such as cherries, pears and peaches but not grapes], and stored grain, and consuming and spoiling livestock food and water. They may spread other agricultural pests (such as nematodes and weed seeds). In exceptional cases (e.g., consumption of alfalfa weevil and cutworms) HOSP have been useful as a destroyer of insect pests, however under normal circumstances its choice of insects is often unfavorable (Birds of America, 1917).

HOSP droppings and feathers create janitorial problems as well as hazardous, unsanitary, and odoriferous situations inside and outside of buildings and sidewalks under roosting areas. They can contaminate and deface buildings with their nests and acidic droppings, which can damage the finish on automobiles, block gutters (with nests), and create fire hazards (e.g., when nesting around power lines, lighted signs or electrical substations, in dryer vents.)

Last, but not least, they are also a factor in dissemination of about 29 human and livestock diseases and internal parasites (Weber 1979) such as equine encephalitis, West Nile (they are carriers, but it usually does not kill them as it has killed crows in the past), vibriosis, and yersinosis, chlamydiosis, coccidiosis, erysipeloid, Newcastle’s, parathypoid, pullorum, salmonellosis, transmissible gastroenteritis, tuberculosis, acariasis, schistosomiasis, taeniasis, toxoplasmosis, and trichomoniasis; and household pests like bed bugs, carpet beetles, clothes moths, fleas, lice, mites, and ticks. Note that other wild birds may also have these diseases and parasites, but because of numbers and typical nesting locations, HOSP may be more likely to transmit them to humans and livestock.

PROLIFERATION: House Sparrows may raise 2-5 (average of 3) clutches of 3-7 chicks each breeding season, (averaging 20 chicks per season) which fledge in 14-16 days. They start claiming nestboxes early in the season (February and March). Since they are relatively long lived (up to 13 years), one pair can at potentially quintuple the population in one year. "If unchecked, a breeding pair can grow to over 2,000 birds in two to three years." (Bird Barrier America, Inc.) (Using some conservative assumptions, I calculated one pair could theoretically increase to 1,250 birds in 5 years.)

• Head injuries are typical. Adults or nestlings attacked by HOSP usually (but not always) have visible evidence of pecking/hematomas on the top of the head (sometimes featherless crown or back) and in the eyes. Victims of an attack may be found dead inside the box.
• Eggs may be pecked in the nestbox (but usually not a pinhole like a House Wren piercing); or removed from the box, and found nearby or underneath it, with contents (unless they are later eaten by something else like ants.) May disappear one by one, during daytime.
• Small nestlings may be removed from the box and found nearby, dead or dying (note predators will generally pick them up if on the ground for any length of time so they no corpses may be found). They may have a broken neck only or pecked heads/eyes.
• HOSP may harass parents so they are unable to feed young, which then starve. They will be seen driving the parents from the box.
• Afterwards, if the HOSP elect to use the box (which does not always happen), they may be seen perching on top of it, or going in and out.
• HOSP may build their own nest on top of a corpse. (Sometimes they do not use a box after an attack). See photos of nests and eggs. Their poop kind of looks like a noodle - white and gray in color.
• Both males and female HOSP will attack, sometimes teaming up.
• See more photos (warning: graphic) and accounts of HOSP attacks.
• NOTE: Another small brown bird, the House Wren will also peck eggs (usually two small holes), remove eggs from a nestbox and may remove very young nestlings. Shortly thereafter sticks usually appear. See info on how to deter House Wrens.

The House Sparrow (Passer domesticus) is sometimes referred to as the English sparrow. HOSP are not native to the U.S. They were deliberately introduced in multiple locations in the late 1800's, and are now established throughout the lower 48 states. See HOSP History for information on their introduction and why they have proliferated, and HOSP photos for pictures of nest, fledglings and adults.

Adults are short, stocky birds, 5.75-6.25 inches long (smaller than a bluebird, larger than a chipping sparrow/House Wren) with thick bills. The back is brown with black streaks. Both males and females have a dingy grayish/buff breast without stripes. The tail is short compared to other sparrows. The song is an boisterous, non-musical, monotonous single-note chirp.

• Adult males have a black, v-shaped bib on the breast under the beak (darkest during breeding season, lacking in juveniles), grayish-brown feathers with a white horizontal bar on the wing, and gray on the top of their head with chestnut below (not a chestnut cap like the chipping sparrow.) The beak may be pink/yellow/brownish or even dark black.
• Adult females are harder to identify, but are dull gray with a light streak at and behind the eye.
• Juveniles: Young look like females but are more brown above and more buff-colored below, with pinkish bills, legs and feet.

Before using any active management methods, you must be able to positively identify a House Sparrow. A good bird book like Sibley's is invaluable in this regard. Some other "brown birds" (SEE PHOTOS) sometimes confused with the House Sparrow are listed below. Only wrens and rarely house finches will use a nestbox. When in doubt, let it out!

• House Wren and Carolina Wren - smaller, long pointy beak, tail often held upright
• chipping sparrow - smaller, mature adults during breeding season have a chestnut cap, strong dark eyeline.
• house finch - plain head, striped/streaked breast
• Eurasian Tree Sparrow - brown crown instead of the HOSPs' gray crown, and a black spot on its cheek that the HOSP doesn't have. Also non-native, will use a nestbox, slightly smaller than a HOSP.
• other song sparrows (e.g., white throated).
• Harris's Sparrow - male has a black bib, but the head is black, and it is about 1" larger than a HOSP, longer tail.
• Brown-headed cowbird (female) - larger, legs are gray-black (not pinkish like a House Sparrow), with fine streaks on breast.

None of these birds (except the House Wren, which is native) will bother other cavity nesters. Generally only the House Wren and occasionally the Carolina Wren will utilize nestboxes with a 1.5" entrance hole. Many, but not all, true sparrows have striped breasts.

A HOSP nest is a loose jumble of odds and ends, including coarse grass (with seed heads), cloth, feathers, twigs and sometimes litter, and occasionally a sprig of green vegetation or roots. It is often tall (arcing up the back of the nestbox) with a tunnel-like entrance. Eggs are cream, white, gray or greenish, with irregular brown speckles.

Droppings: HOSP may roost in nestboxes. It may be difficult to tell what species is roosting from droppings. Keith Kridler says bluebirds normally have seeds from fruits or berries in their droppings. Chickadees and titmice and even House Sparrows normally have droppings without large seeds. Normally the House Sparrow male will have firm droppings or tiny noodles of feces often right below the entrance hole on the floor of the box. Also the roof of the box may serve as a place for him to spend a lot of time singing and watching for a female. He often leaves a lot of droppings on the roof of the box, as will a Mockingbird perching there will. Again the Mockingbird at this time of the year is feeding on fruits and berries.

MIGRATION: The HOSP is an intelligent, hardy bird with no recognized migration pattern. Although they are widely distributed as a species, adults generally remain within 2 to 6 km (1.24 - 3.8 miles) of where they were hatched. Flocks of juveniles and non-breeding adults may move 6 to 8 km to new feeding areas (3.8 - 5 miles overall.) My husband noticed that new HOSP seem to "appear" after a storm like a Nor'Easter - perhaps they get blown into new areas. They are common in agricultural, suburban, and urban areas. The only areas they tend to avoid are woodlands, forests, large grasslands, and deserts.

It is better to have no box at all than to allow House Sparrows to reproduce in one. House Sparrows are non-native invasive birds that are not protected by the U.S. Migratory Bird Treaty Act or Canadian federal, state and provincial regulations. U.S. federal law permits removing or destroying HOSP nests, eggs, young, and adults. Generally, they may be removed by individuals using any method except poison, or at night with guns with lights. Be aware that some states and municipalities have issued statutes/ordinances that protect all birds, both exotic and native, and also may require a permit to trap or euthanize HOSP, or have other applicable requirements.

Some people feel that no animal should be physically harmed and will prefer passive management, and I respect that. There are a number of options available. However, be forewarned that, sooner or later, many people who stop short of trapping will lose eggs, young and adults of native birds to a HOSP attack.

Some people want to "let nature take it's course." However, as noted above, House Sparrows are not naturally occurring in the U.S., and were introduced by humans. If you allow HOSP to breed in any location, you will be increasing future competition for nest sites. Some passive methods still allow sparrows to harass birds nesting in natural cavities, to harass and evict bluebirds as they are selecting nestboxes, building nests, and mating, and to destroy eggs and nestlings. Therefore, a combination of both passive and active methods will be most effective.

I am not recommending one management method over the other - you must make your own personal choices. One bluebirder said "If one won't - or can't (totally understandable) - try to protect blues from HOSP, possibly a greater disservice is being done to offer boxes to blues in which they are near-certain to die than to offer no boxes at all....unprotected boxes often become HOSP factories."

I do not believe that HOSP are evil (see discussion), but I do believe they need to be managed to enable bluebirds and other native cavity nesters to survive and thrive. Unfortunately, most passive methods are limited in their effectiveness. If House Sparrows are in your area, and you do not take steps to manage the population, the likelihood of successful nesting by native cavity nesters birds will be reduced or even eliminated.

Personally, I have not found that large HOSP populations can be successfully controlled without employing active methods. Initially, it may feel like sticking your finger in a dike, but you can get the population under control with courage, persistence and time. HOSP can be virtually eliminated in the area of a small trail using a combination of passive and active methods. You can create an almost sparrow-free zone or oasis locally. However, vigilance is required. Because they are so prolific, skipping even a year can allow HOSP populations to rebound to problem levels.

In the meantime, find out the name and number of your closest licensed wildlife rehabber, as you may need their help when HOSP attack.

Passive management involves discouraging HOSP feeding and nesting. With all deterrent methods, it is important to evaluate efficacy over time, as birds may become accustomed, or behavior may vary from season to season (e.g., breeding vs. fledging vs. roosting). Some of these methods may also deter desirable birds, but may be necessary until you get the HOSP population in your area under control. If you are in a suburban area, you will probably need to recruit neighbors into using the same methods. See the House Sparrow advisory you can give to people with neglected nestboxes where HOSP are allowed to breed, or who are feeding millet/cracked corn birdseed that attracts HOSP.

Note that some of these methods (monofilament, sparrow spooker) allow sparrows to harass bluebirds as they are selecting nestboxes, building nests, and mating.

It's possible neophobia (fear of novel objects) may be a factor with HOSP being deterred by sparrow spookers, monofilament, magic halos, and different box styles. However, a HOSP will readily investigate a new wooden box that is put up.

After a bluebird has claimed a box and laid its first egg, immediately install a sparrow spooker. These are extremely effective, protect the nest 24/7, and nesting bluebirds will readily tolerate them. They can be made with one vertical dowel/stick that has two or three horizontal dowels/chopsticks extending out of the top, with 1/2" x 6" strips of mylar hot glued/duct taped onto them, hanging over the roof and near the entrance hole. See instructions and drawings. If properly constructed, it is a life saver. One weather-resistant, ready-made version is available commercially.

• Do not offer seed that contains white proso millet (the little round seeds that come in many mixtures) or cracked corn (or offer seed mixes with less than 35% millet and 15% cracked corn if you want to attract juncos, native sparrows, and mourning doves). Do not feed bread. Black oil sunflower seeds, nuts, and thistle (niger/nyger/nyjer) may not be preferred by House Sparrows, but may be eaten if food is scarce, so selective feeding is not an effective deterrent. (Brad from Wisconsin reported that HOSP in his area prefer black oil sunflower to striped). If feeding thistle, choose a goldfinch style feeder that requires birds to hang upside down to feed (with the feeding port below the perch.) Note that in some areas, HOSP will eat anything from any style feeder. HOSP will eat suet.
• Put a hoop device such as the Magic Halo on your bird feeder, which repels an estimated 88-94% of HOSP in winter, 84% of summer. Other birds are not repelled. Hang hobby wire (28-30 gauge or the thinnest lightest weight you can find) from the hoop at 4 equidistant points, weighted with a fishing weight or metal nut so incoming birds do not get tangled in it. See more info on the Magic Halo.
• If other people in your neighborhood are feeding HOSP, talk with them and give them a copy of a HOSP advisory to explain the impact to bluebirds.
• Try feeding black oil sunflower seeds (which HOSP may eat) in Duncraft's smallest "satellite globe" feeder (one portal) hung from a wire or string, so it swings in the breeze.
• Use seed port wires. In open port tube feeders with perches, bend a 10" piece of flexible wire in half. Feed the wire through the port, loop it over one perch and pull it tight and tie it off around the other perch. The strands of wire make it harder for the sparrow to get seed out of the feeder, but do not affect finches, chickadees, nuthatches or other desirable songbirds.
• Trim wooden/plastic perches back to less than 5/8" to deter HOSP, grackles and starlings.
• Use plastic mesh cut to fit in the bottom of a hopper type/trough feeders.
• Remove bird feeders altogether.

• Avoid placing nestboxes near farmsteads, feedlots and barns (which offer plenty of food, shelter and nesting sites), and human occupation (e.g., buildings or areas where people are feeding cheap birdseed).
• Place nestboxes 0.07 to 0.5 miles or more from buildings and farms, since HOSP are usually associated with human activity if you are not willing or able to actively manage HOSP populations.
• Leave boxes plugged (e.g. with a rubber drain plug available at the hardware store), until the desired occupant is ready to move into the area (to prevent HOSP roosting and claiming boxes early in the season.)
• Try relocating boxes that have been claimed by HOSP in previous seasons.
• For a box claimed by a HOSP: Generally nothing will stop them from nesting except making the box unusable, which may encourage them to move elsewhere. You can:
  • remove the box
  • plug the entrance hole ($1.79 rubber drain plug from a hardware store fits in the 1.5" hole or crumpled up newspaper)
  • leave the door/roof open
  • remove the door
  • Some people suggest placing a rubber snake in a box claimed by HOSP to scare them off (with about a foot of the body and head sticking out of the box.) A HOSP may proceed to build its nest on top of the snake.
  • Placing a cat food can/tub constantly filled with water on the nestbox floor may also deter HOSP from nest building.
• Height: Boxes 3-5 feet off the ground MAY not be preferred by House Sparrows, but should not be used for native birds where there are climbing predators (cats, raccoons). Note that some HOSP will nest near the ground, even 24" high, especially if nest sites are in short supply.
  • HOSP will nest in hanging boxes. Hanging the nestbox from a wire has been suggested as a deterrent, but HOSP will nest in a hanging/swinging box or gourd.
  • If a HOSP shows an interest in a box that bluebirds have claimed, immediately lower the height (temporarily) of the bluebird house to about 4 feet. Put up another house a few feet away at a much higher height (around 7-9 feet) and if possible closer to a nearby house or other man-made building. The House Sparrow will often move to the new, higher house. This can facilitate inbox trapping.
• Timing: Since HOSP start claiming nestboxes early in the season (February/March) leave boxes closed until April 1 in northern states. You can stuff crumpled up newspaper in the holes or plug them with a bathtub drain plug.
• HOSP apparently do not "imprint" on the nest site where they were born, but they may nest in a site where they roosted during the winter, so it is important to deal with roosting birds also.

Clustering and Pairing Nestboxes

Putting up an additional box(es) does not DETER HOSP nesting. It is not possible to saturate an area with enough boxes so other species can safely nest. HOSP may actually be more attracted to boxes that have nesting material in them. If you do use this method, monitor more frequently (e.g., 2-3 times per week, especially at the beginning of nesting season) and then trap HOSP attempting to use the extra boxes. If you do not, "House Sparrows will reward your kindness by killing your bluebirds...." - Bob Orthwien

Because HOSP are colonial nesters, they will nest in close proximity to other HOSP. HOSP have nested in boxes 10 feet apart (Daniel 1995.) Also, perhaps out of an instinctive desire to reduce competition, HOSP may actually prefer a nestbox occupied by other birds even when it is surrounded by other empty boxes. They may also end up using or controlling both boxes.

If you only have one nestbox, HOSP may evict nesting bluebirds. If there is an empty box in reasonable proximity (e.g., one in front yard, one in back), the HOSP may choose the empty box, especially if the bluebirds that are farther along in the nesting cycle. As noted above, in some instances, HOSP will still focus on the occupied box, but then perhaps the native birds will move to the empty box. This can give native birds a chance to start nesting, especially on a large trail.

On the other hand, a box may remain empty for weeks, and as soon as another native bird chooses it, HOSP move in.

Providing additional boxes has the added benefits of providing additional houses for native species, and offers a choice to native birds (since there may be something about one nestbox they don’t like). If HOSP do start nesting in one of the boxes, they can be trapped during in the incubation stage and the other nestbox is not tied up while you are trapping.

Kate Arnold has noted that House Sparrows settle down when tending to their nest, rather than rushing around to other nestboxes, and finds it is easier to catch both the male and female during the incubation stage, as their behavior is so predictable.

Orthwien reported good success with triple boxes (spaced 7 yards apart). He quickly trapped the male HOSP and cleaned out the box, and in 8 years did not have a bluebird or Tree Swallow killed or their nests usurped in these triple box siets.

With regard to pairing:

• If bluebirds are in one of a pair of nestboxes, and Tree Swallows are in the other box, they may work together to defend the boxes against HOSP.
• However, if there are no Tree Swallows, it's POSSIBLE (pure speculation here) that pairing could distract the bluebirds (which may try to defend both boxes) and actually make defense efforts less effective.
• If a HOSP is nesting in a paired box, any bird investigating or using the other box may risk attack before the HOSP can be trapped.

• Be aware that even though HOSP may not "prefer" to nest in certain types of nestboxes, they may still enter them for the purposes of attack, and may use them if nesting cavities are limited or competition for sites is fierce. They may also enter them if they are being used by another bird, due to their competitive nature.
• Monitors prepared to trap House Sparrows have the option of adding a HOSP-resistant box near a contested Bluebird box. Bluebirds will usually move into the HOSP-resistant box. with House Sparrows taking the standard wooden box where they can then be trapped and euthanized. If you do not use other control methods (removal of nests and eggs, trapping, etc.), you risk HOSP attacks and are enabling HOSP populations to explode.

Type of boxes HOSP MAY avoid or not prefer: Again, despite claims you may read, no one has invented a nestbox yet that HOSP will not use. One of the reasons HOSP are so widespread is that they are very adaptable. HOSP tend to be wary of change, and may initially avoid a new type of box. But over time (or due to nest site competition) they may become accustomed to it, and use these boxes.

Unfortunately, some HOSP-resistant boxes are not ideal for bluebirds either in some way: e.g., too shallow for safety (allowing predator access), small interior space (especially a problem for Western Bluebirds), entrance hole is too big, or open top (Bauldry design) allows rain to enter. Thus bluebirds using it may have a greater chance of a failed nesting.

• House Sparrows may be reluctant to use a Gilbertson PVC box or other boxes made of PVC pipe.
• HOSP may avoid a slot box (e.g., Efta or Hughes designs), perhaps preferring a circular hole and a deeper cavity. I have seen HOSP readily nest in a regular slot box. Loren Hughes has had few HOSP attempts in the Hughes slot box.
• Shallow box: Put a block of wood on the floor of a nestbox to make it more shallow (3-5" deep), and thus possibly less attractive to HOSP. Unfortunately, bluebirds are perhaps less likely to use a box that is less than 4" deep, so you may wish to remove the block of wood if you are successful in having the HOSP abandon the box. There is some concern that starlings may be more likely to prey on eggs and young in a shallow box, however Davis (Bluebirds and Their Survival) indicated this seldom occurs.
• In my experience, HOSP do not avoid Gilwood box (for plans see Audubon Society of Omaha.) The Gilwood box has a small interior that starlings prefer, and the wire across the large entrance hole actually makes the hole smaller thus preventing starlings from entering. HOSP in my area seem to actually prefer the Gilwood over regular NABS boxes.
• See other experimental boxes.

Larger Entrance Facilitating Escape (two-hole box, Slot box, perhaps Peterson)

• A larger entrance provides an avenue of escape in the event of an attack. While these boxes will not protect eggs/nestlings from attack, they may at least enable adults to survive. IF the HOSP moves on (they can be very persistent), the native birds can proceed to nest.
  • In this video clip of a HOSP attack, it looks to me like the elongated Peterson hole shape helped the second bird escape.
  • Some monitors expect that a male, or an incubating female may choose not to abandon the nest if a HOSP enters.
• A two-hole box is not technically a HOSP-resistant box. House Sparrows will readily use them in the absence of bluebird competition. But Linda Violett has found that somehow bluebirds seem to learn to control the box, despite HOSP competition. The large interior may have something to do with it (maybe the bluebird can manuever better?)
  • As noted above, the second hole provides an avenue of escape for adult birds in the event of an attack. Maynard Summer witnessed BOTH the male and female HOSP entering a two-hole box at once to attack and kill a nesting chickadee. But of dozens of HOSP/Western Bluebird battles in 2-holers over an eight-year period on Linda Violett's trails, only a handful of adult bluebirds are reported to have been trapped and killed by HOSP in 2-holed boxes. Its use appears to have reduced HOSP problems on the Yorba Linda trail in CA, and no adult bluebirds have been killed in 2-holers by HOSP on an infested trail in La Mirada (see online log notes).
    
    
• Also see experiments with light

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• LIGHT: Some speculate that HOSP prefer a dark, deep cavity. Others believe that light is not a significant factor, as HOSP will nest in the open (e.g., on top of a sign), although these nests tend to have a tunnel-like entrance. Varner (1964) felt that bluebirds also prefer darkness inside the box, so a design that lets light in might also deter bluebirds somewhat. The main concern is designs that let in so much light that the interior can overheat, or let in nasty weather.
  • Open-top "Bauldry" boxes are no longer recommended by NABS. They have a 3" hole in the top, covered with hardware cloth. Supposedly HOSP don't like a wet nest. Unfortunately, it is not healthy for bluebird nestlings either, and can increase the likelihood of fatal hypothermia. These boxes may still be used by HOSP.
    • One birding store owner tried covering the 3" hole with plexiglas (on the theory that light deters HOSP), but the heat killed the eggs and nestlings. However, he did indicate that bluebirds appeared to prefer these boxes (Zimmerman personal communication, 2004)
  • Boxes with 1/2 of the roof made of Plexiglas (covered during warmer weather to prevent overheating) do not appear to deter HOSP long term.
  • Boxes built with extra light entering the box (vents, slots, two holes, plexiglas) are all used by HOSP. HOSP have been known to use a nestbox that has no roof at all. I don't know whether they are really not PREFERRED by HOSP.
  • Removing most of the wood bottom of the nestbox and covering it with circles of Plexiglas, or with 1/4" hardware cloth so that the bottom looks open to a bird looking inside the nestbox does not work long-term (Kridler on Dick Walker experiment).

Experiments with light continue:

• We know that HOSP WILL use a box that lets more light in (see above.) The question is, will they AVOID a box like this, or PREFER a box that is darker over a lighter one when given a choice? And will native cavity nesters use a box with a lighter interior?
• The bigger entrance hole in the Gilwood (which HOSP tend not to prefer) or a 2-hole box does let in more light.
• Loren Hughes experimented with drilling a 2" hole in the side of the nestbox near the top. Then he stapled a 3" square piece of plastic cut from a milk jug over the hole on the outside of the nestbox. Note that the plastic may become brittle over time, and need to be replaced. He tested coating it with KRYLON Crystal clear acrylic spray to see if it lasted longer. Initially, HOSP seem to lose interest in the box (possibly due to neophobia - fear of something new). Some HOSP packed grass against the acrylic to block out light. He discontinued this experiment.

Other Nestbox Design Issues

• Do not include a perch on a bluebird nestbox. House Sparrows find them useful in maintaining possession of boxes they have managed to occupy. (Zeleny, 1976). However, a HOSP can use a box without a perch.
• Hole Reducers: For the smallest cavity nesters (e.g., chickadee, titmice, nuthatch) use a hole reducer (smaller than 1.25") to exclude almost all HOSP and protect eggs and birds in the nestbox. (Tree Swallows apparently require at least a 1 3/8" hole. Unfortunately) HOSP tend to prefer a 1.5" diameter hole. However, smaller HOSP may be able to enter smaller holes, and HOSP size depends on latitude and winter temperature, with smallest birds along the Louisiana and s. California coasts and in Mexico, and largest birds in Canada and the Rocky Mountain and plains region. Frank Navratil reported that for entrances (after HOSP were allowed to build nests, reducers were placed on boxes):
  • ROUND
    1 1/4" diameter allows HOSP entry.
    1 1/8" diameter stops entry. (NOTE: Keith Kridler of TX has had HOSP nest in boxes with an exact 1 3/16" hole. Phil Berry of FL reported HOSP entering via a 7/8" restrictor used on a box with Brown Headed Nuthatches nesting.)
  • HORIZONTAL SLOT
    1 1/2" x 1" slot allows entry.
    1 1/2" x 7/8" stops entry.
  • VERTICAL SLOT
    1" x 1 1/2" slot allows entry.
    7/8" x 1 1/2" slot stops entry
    • Note: Mike Donahue of Seattle had a HOSP build a nest in a Violet-green Swallow box with this slot size.
    • Malcolm Rodin of B.C. uses a horizontal oval hole on Violett-green swallow boxes that is 7/8" with two 5/8" holes on either side, with a hardwood block hole guard on the outside, and has been successful in excluding mature male HOSP.
  • If a sparrow spooker doesn't work for some reason (rare) and the babies are under constant attack by HOSP but are close to fledging, you could install a 1" hole restrictor, which allows the parents to continue feeding but they will not be able to remove fecal sacs, and may have trouble accessing weaker nestlings to feed them. Remove the restrictor when the babies are due to fledge.
  • Bob Orthwein noted "Even though house sparrows can not enter the 1 & 1/8" entrance hole, these weird birds will often mercilessly harass nesting chickadees by hanging on the box, poking their heads in the entrance hole and attacking the chickadees entering and leaving the box. The sparrows will do this even with a nearby empty box that they can use. A wren guard stops this harassment." See more information about how to make a wren guard.
  • On a HOSP-infested park trail in CA, Linda Violett found that while boxes with a 1.25" hole face guard that was about 3/4" thick did not stop all HOSP action, it significantly reduced HOSP activity/interest. This may (?) be why I never catch HOSP in Van Ert's Urban Sparrow Trap, which has a 1.25" reducer on it to prevent bluebird trapping.
• Decorative nestboxes should either have a hole 1 1/8" in diameter or smaller, or the hole should be plugged or painted on. (See handout on unmanaged nestboxes, which can become HOSP breeding grounds.)
• Floor size: Some people (e.g. Varner 1964) speculate that HOSP may prefer boxes with a larger floor size to accommodate their bulky nest. Thus a floor size of 3.5 x 3.5" or 4 x 4" may be less attractive to HOSP. Note that a smaller floor size can result in crowding (impacting sanitation, vigor, and increasing the effect of excess heat.) I have had HOSP readily nest in smaller NABS style boxes.
• Can Trick: For a nestbox with repeated HOSP nesting attempts, create an illusion that the interior is very small and cramped. The HOSP may then abandon the box. Take an empty small (e.g., 8 oz.) clean, dry tin can, and place it inside the box so that when the bird enters the entrance hole they end up in the can. You can wedge the can in place with a small block of wood between the bottom of the can and the rear panel of the box. Leave it in place for about 2 weeks. Once the HOSP abandon, perhaps a native bird will find and use the box. (Thanks Rudy from Maryland).
  

	Use clear fishing line. The red color in the photo is just so you can see where the fishing line goes.)

For some reason, HOSP (but NOT bluebirds or Tree Swallows) tend to be spooked by monofilament (fishing line)/hobby wire. They will fly towards it, flutter in place, and then fly away. It may be due to their eyesight (since they are primarily seed eaters vs. aerial feeders) and flight pattern (approaching with wings spread.)

This effect may wear off over time, or when nest site competition is fierce. While not 100% effective, HOSP appear to prefer nestboxes without monofilament over those that have it. This works better with adults, as juveniles are less fearful.

Put up the monofilament BEFORE the male HOSP starts looking for nesting sites and "bonds" with a box. Once he has bonded, he may tolerate it.

• String 6-20 lb. clear fishing line (pulled tight) on either side of the entrance hole (parallel). Fine fishing line may work better than thicker line, as it is "spookier."
• The Bluebird Society of PA recommends spacing the line 1.75" apart (on either side of the entrance hole.)
• You can use push pins or eye hooks to guide line. Make sure you can still open the door for monitoring. I also put two screws in the side of the roof and hang fishing line from screws.
• WARNING: To prevent the line from being pulled into the nestbox and tangling up nestlings, put a fishing weight or metal nut on the end of the dangling lines. Remove any fishing line that breaks or degrades over time. If loose monofilament ends up inside the box, it can kill a nestling or trap it so it can not fledge. Dispose of line properly by cutting it up and throwing it in the trash.
• Another layout shown in the drawing (which I haven't used yet) involves four eye hooks surrounding the entrance hole, with the mono threaded through the eyes. Also see Sue's simplified version.
• At feeding sites, lines spaced 2 feet apart should repel 89-98% of HOSP. Also see Magic halo to repel HOSP from feeders.
• Joel used two 18" metal fishing leaders (for pike etc.), crimped on 2 split shot weights, grabbed 4 staples and in less than two minutes put up a deterrent that kept HOSP from landing on his chickadee box.

Removing Nestboxes: Some people recommend not putting up nestboxes if there are HOSP in the area, as it may invite catastrophe. However, if control methods are used, bluebirds may be able to successfully nest while you work on a longer term HOSP control program.

Sometimes people have problems with HOSP and give up immediately, and take their boxes down. Keith Kridler noted that if you do this, the next generation of bluebirds will probably move down the street, perhaps into a nestbox that no one monitors or cleans, and no one will ever report that House Sparrows or Starlings continued to evict or kill bluebirds year after year.

Exclusion (e.g., from roosts) : Most HOSP go to their main roost 15–30 minutes before sunset. Note: Some sources say that HOSP are not "hardy" outside in cold weather, and that one week of temperatures at or below 10*F will decimate the sparrow population (even if they have adequate food) if they cannot get into warm building to roost at night. Once their favorite spots (cavities in buildings) are gone, the HOSP are more likely to go into a trap box.

• DO NOT PROVIDE ACCESS to bird seed, grain, or food waste.
• CLOSE OFF ALL OPENINGS in warehouses, garages and farm buildings
  • Put up plastic BIRD NETTING (attached with tacks or pieces of lath), or wood, metal, glass, masonry, or 3/4" rust-proofed wire mesh over upper structures like rafters where HOSP can roost or nest and ventilator openings that provide access to buildings (see photo.) This can work on carports.
• REPLACE OR COVER BROKEN WINDOWS in upper stories with wire mesh, plastic, wood or sheet metal
• BLOCK OPEN DOORWAYS with full-length, hanging plastic strips (10 - 15 cm wide)
• USE 'GREAT STUFF' EXPANDING FOAM to fill and/or seal up cavities in out-buildings and barns. Wad up scraps of chicken wire and stuff them into any place that you see HOSP trying to nest, then squirt in 'Great Stuff.' After it dries/hardens, shave off the excess that oozes out. You can paint right over the dried/hardened foam.
• SCREEN poultry houses and feeders to exclude sparrows; seal all openings larger than 3/4"
• ELIMINATE PERCH SITES by fitting ledges and rafters with slanted boards at a 45 degree angle.
  

Plant Management

• Remove vegetation they congregate in while resting (e.g., privet hedges or hedgerows, multiflora rose, thickets, brush piles, and ivy growing on walls which may also be used for nesting.) However, note that other native birds may use this vegetation also. Some shrubs or trees can be pruned to open them up (which is usually good for the plant too) so they are not as useful as hiding places for HOSP.
• Protect small crop areas with plastic bird netting in situations involving high-value crops, such as grape and berries. Do not leave any openings at the bottom of netted crop areas.
• Severely prune trees and shrubs with thicket-like branches used by HOSP as cover. This will also enable predators like Cooper's hawks to hunt HOSP more effectively.
• Remove dead fronds from palm trees to eliminate roosting sites.
  

Chemical Repellants

Use of Bird-X "Bird-Proof Repellant Gel" is NOT recommended. Although it is advertised as "a non-toxic, sticky chemical that makes a surface tacky and uncomfortable to birds" it is, of course, not specific to House Sparrows. Any bird that lands on it may get it on their feathers, which can interfere with their ability to fly, resulting in death by falling/starvation.

Also see what doesn't work

Unfortunately passive methods have limited effectiveness. Active management includes rendering eggs infertile, egg and nest removal, HOSP trapping, shooting, etc. Since House Sparrows are classified as pests and are not protected by federal law, they may be quickly and humanely euthanized.

Trapping HOSP can dramatically increase successful nesting by native birds. After dedicated trapping, one trail monitor in California saw successful bluebird fledging almost double in the first year. Some monitors feel they would have nothing but HOSP on their trail if they did not trap.

Relocating a HOSP would be like trapping a rat and letting it loose in your neighbors yard. (A Purple Martin Conservation Association publication says "Some people choose to kill the birds, others transport them 10 to 20 miles away and release them. This latter option, while easier on some people's conscience, really serves no purpose other than to waste fuel....House Sparrows may settle into the area where released, but they will cause others of their kind to disperse outwards. In other words, it's analogous to trying to bail the water out of a boat by taking buckets of water from the back and dumping them in the front.") HOSP may need to be relocated 25 miles or more away. Relocating any wildlife without a permit is illegal in some states.

See Euthanizing HOSP for methods that have been used. Dead sparrows can be frozen immediately, and donated to raptor recovery centers to feed their injured birds. Contact the organization for details about what they will accept. They may also be suitable food for snakes.

Steve Kroenke wrote an article on House Sparrow Revenge Syndrome. He posits that HOSP become even more aggressive in response to some active control measures, and may destroy and attack nests of other birds in the area. It is hard to know whether an attack would have occurred anyway, regardless of active management. It may not always happen, and it may not often happen. However, multiple people have reported HOSP taking over another box with an active nest when their own nest/eggs are removed, and in some cases attacking nests in one other box or multiple boxes but not subsequently using those boxes for their own nest.

Ongoing Study of HOSP nest and egg removal on a trail (without trapping): Paula Ziebarth and Darlene Sillick are conducting a study on this issue in Ohio. It appears, based on results in the first year, that HOSP nest removal, especially after eggs have been laid, is extremely dangerous for native cavity nesting birds. It may set up an "ecological trap" for native nesters that believe it is empty and available. Thus they enter to check it out, and may be attacked and killed. In a paired box situation, HOSP may abandon the box where they were unsuccessful (where the monitor just removed nest and eggs) and kill whatever they find in the adjacent box so they can use that one.

It is possible that loss of a nest/eggs may result in a spike in testosterone which triggers re-nesting, and/or more aggressive behavior. Although I'm not familiar with any scientific studies on this, Keith Kridler discussed a study where male HOSP injected with testosterone began vigorously defending their chosen nestbox and searched out and removed other cavity nesters using boxes close to their territory. It may also be a survival mechanism.

One trail monitor experienced an increase in HOSP attacks on trails in response to removing a nest, or all HOSP eggs prior to capturing the male; but NOT in response to egg piercing, or trapping and removing a male or female. Another experienced takeovers of other boxes upon removing a HOSP nest with eggs, but NOT in response to addling and replacing the eggs in the HOSP nest.

Others believe the HOSP "rampage" concept is a myth. A trail monitor in California has destroyed dozens of HOSP nests and smashed hundreds of eggs inside and outside the nestbox, without witnessing any "HOSP rampages" or behavior that might be construed as retaliatory.

If your native chicks are close to fledging and you are concerned about the possibility of takeover/revenge/ rampage, to be on the safe side it might be wise to wait to take certain active HOSP control measures such as removal of nests with eggs, or removal of the female only. (Trapping the pair eliminates that threat). In the meatime, I'd strongly recommend using a Sparrow Spooker on a nestbox being actively used by native birds if HOSP are in the area. You can also addle the HOSP eggs so they are nonviable and return them to the nest. (This will not help with single males.) You may also want to trap both the male and the female to completely eliminate the possibility of an attack. It is easier to trap HOSP with an active nest in the box. See inbox trapping.

After trapping a HOSP, you can trim both HOSP wings prior to release so they can not attack bluebirds/enter nestboxes to reproduce. See photo demo and more info. Fawzi Emad reports that HOSP tend to become docile after trimming. This option is best in areas where the HOSP population is not huge. Using this technique, Emad reported that the population got under control in 2-3 years.

Trimmed feathers re-grow in about 6 months. (McLoughlin). It is important to trim both wings - if you only trim one, the bird will not be able to maneuver at all and will basically become cat food. See discussion on Fawzi's website.

• WARNING: Before interfering with any HOSP nest or eggs, you must first be SURE it really is from a HOSP! It is illegal to disturb the nest of any native bird. People have confused nests of nuthatches, Tree Swallows and Western Bluebirds with those of HOSP. See photos of HOSP eggs, HOSP nests, and a description of a HOSP nest.
• You can try removing HOSP nests and eggs. On some trails this is enough to control HOSP populations. Occasionally birds take off after one or a few removals. However, since the male bonds with the box, they generally immediately rebuild, and drive off other native birds that might want to use the box. Also, removing nests doesn't mean the HOSP has given up the box, which means if another bird tries to use the box, the HOSP may attack them or their eggs/nestlings. Some people claim that males get enraged by removal of nests or destruction of eggs, and will go on a rampage. Others feel this is a myth.
• BE SURE the nest actually belongs to a HOSP. (See HOSP photos and webpage on nest and egg ID). Nests that may be confused with a HOSP nest include that of the Western Bluebird and Nuthatch. Birds other than HOSP occasionally use "trash" in their nests, or may build an untidy nest.
• If you do remove nests, be prepared to do regularly (at least every 10-12 days), as HOSP rapidly rebuild. If you are also ground trapping, save nests for use as lures.
• Linda Violett has successfully controlled HOSP populations on a trail in California without trapping. She uses large two-hole boxes and removes nests and eggs. See her keys to success summary.
• Some (e.g., Fawzi Emad) indicate they have had success pairing a nestbox for HOSP with a bluebird box, letting the HOSP lay eggs and then rendering them infertile, keeping the HOSP occupied without allowing them to reproduce. I would still be concerned about the potential for territorial aggression by the male HOSP against birds in the paired box, and the loss of an available nest site for native cavity-nesters.
• If you are knocking down nests in rafters etc., clean up and remove the nest to pevent reuse or spread of nest parasites. Try exclusion to prevent re-nesting.
• Remove all eggs but leave one and allow HOSP to raise one chick to keep them occupied and to reduce attacks on other boxes. THIS IS NOT A PREFERRED OPTION as this nestling will grow up and cause the same problems that adult HOSP cause. The grown up may bond with the box and the territory.

Rendering Eggs Infertile

If eggs are rendered infertile, the female will generally continue to incubate them for some time (2-4 weeks, after which she will abandon the nest), keeping her from reproducing or competing with other nesting sites. IF NOT DONE PROPERLY EGGS WILL HATCH. The most humane approach is to render the eggs infertile as soon as laying has ceased and incubation begins. Incorrect or incomplete piercing and shaking can leave the embryo alive but deformed. Mark treated eggs with a magic marker if the female is still laying. Also, sometimes birds realize the eggs are not viable, and remove them and lay new eggs.

Addling is a good choice if the nest is not in a nestbox, which makes it harder to trap.

• Oiling: (best method) Dipping or rubbing eggs with 100% food grade corn oil keeps air from passing through the shell so the embryo cannot develop. Oiling is reported to be highly effective (between 95-100%). Coat the entire egg, and allow it to air dry before returning it to the nest. Do not wet the entire nest with oil, as it will get on the nestbox.
• Piercing: Prick eggs so they will not hatch, and return them to the nest. You must break through the membrane that surrounds the egg white - a shallow prick is not sufficient to prevent hatching. Push a small-size needle or lance (used by diabetics to test blood - available at drug stores) into the large end of the egg. (A pin is generally not sharp enough.) The hole should be small enough so that the contents will not run out and alert the mother that the egg is damaged (at which point she may lay more). Be careful not to break the egg while holding it. Occasionally pierced eggs will hatch, so you might want to addle them first. Store the needle with the sharp point embedded in a cork.
• Refrigerating: Refrigerate or freeze eggs at least overnight. Let them warm to room temperature before replacing them - otherwise the HOSP may remove them. You might keep a supply of sparrow eggs in the refrigerator. Store them in a small craft "organizer"/bead holder with small compartments that protect each sparrow egg from damage (buy in the Wal-Mart craft section.) This is especially useful when HOSP build nests in evergreens, etc., since they are harder to trap than HOSP who nest in a box.
• Addling: Shake eggs vigorously. These eggs sometimes still hatch, so not the best method!
• Cooking: Boil them, microwave them (a few seconds on low or they will explode).
• Dummy Egg Replacements: Replace the real eggs with fake speckled eggs (about 0.9" long) available at craft stores such as Michaels. This may not work as well as real eggs that have been rendered infertile.

• The two main types of traps are ground traps (baited and placed on the ground) and nestbox or inbox traps (used to catch a single HOSP entering or claiming a nestbox.) There are other types (mist net, bottomless pit, tipping can, etc.) that I am less familiar with. They are all live traps, which means they are not designed to kill the captured bird.
• See review of various types by Paula Ziebarth.
• If you only have a few HOSP, go with a nestbox trap, as they are less expensive, effective, and directly address the issue of proliferation and nestbox competition. They may also be more likely to catch the older agressive male. My personal favorite is the Van Ert.
• If populations are higher, get a ground trap. These may be more likely to catch juveniles and first year males. My personal favorite is an escape proof repeating trap like the Deluxe Repeating Sparrow Trap.

• All traps must be checked frequently to ensure that only target birds are trapped. Release native birds immediately. They are not as hardy as HOSP. They may also be killed in a ground trap by other birds trapped with them, as aggression may increase due to stress and close quarters.
• For ground traps, to reduce the likelihood of catching native birds:
  • Use bait types not preferred by native birds, such as bread and millet.
  • Use HOSP decoys. It won't prevent other bird species from entering a trap, but it may deter them somewhat.
  • Use traps designed for HOSP (elevator trap weighted specifically for HOSP, or trap with a tunnel like entrance vs. a Hav-a-Hart). Native birds are more likely to be caught in a funnel trap than in a weighted elevator trap.
  • Elevate the trap off the ground (e.g., on a picnic table, milk crate, yew bush - if it's on a shrub you won't have to clean up underneath. Even a foot or two up will attract more HOSP.)
  • To prevent morning doves (which like cracked corn) from entering the DRST (they jam themselves into the elevator sometimes and can be seriously injured in the process) try putting two nails/screws on either side of the platform (to leave about a 2" space in the middle leading to the elevator entrance), so only smaller birds can enter.
  • WARNING: If you can not monitor a trap for some length of time, or when storing the trap in an outdoor shed etc., do not leave any food in it, and disable it (e.g., use a twist tie or cable tie to wire it open, or turn it upside down). That way if a creature (mouse, native bird) goes in it, it will not die inside.
• For inbox traps:
  • Always check hourly and immediately release a non-target bird. No matter what anyone tells you, some native birds WILL go inside a box that HOSP are using, or an empty box when they are using another nearby.
  • If it does not endanger a native cavity-nester using the box, wait until the HOSP have clearly claimed the box and begun building a nest.
  • If you are using inbox traps on a trail, here is the technique P. Ziebarth uses: "I always make little trail notes on a small notepad and write "SET" (trap set) and circle it whenever I set a Van Ert. Then I cross out the "SET" with a big X when I remove it. This way I never forget which box I have one in."
  • Use a 1.25" hole reducer to exclude most bluebirds. However, monitor carefully: Small male bluebirds can squeeze in a 1 3/8" hole. One monitor lost a Western Bluebird that went into a box with a 1.25" hole restrictor on the outside, and lost a battle with a HOSP inside the box. Bluebirds (especially males) have a tendency to check out local real estate. This works better on a box where HOSP have already started a nest/have eggs and thus are motivated, as otherwise HOSP may avoid a smaller hole.

• Inbox Trap:
  • Get a mesh laundry bag with a drawstring- the kind used for laundering delicates - found in Wal-Mart with ironing board covers etc. Don't use regular mesh as the birds can get tangled in it. A strong clear garbage bag may be used. A dry cleaning bag is not strong enough. A cloth laundry bag with a drawstring can also be used, and may be less scary for the bird, but you will not be able to immediately determine whether it is a HOSP.
  • Remove birds soon as the trap is tripped. When removing birds from nestbox traps, cover the nestbox with a mesh bag, pulling the drawstring tight at the bottom, cinch it, or tie it closed with a pipe cleaner. Open the trap and HOSP will fly out into the bag. Scrunch the bag closed underneath the bird when taking it off the box so it doesn't escape.
  • Open the side of the box or remove the trap. A House Sparrow will immediately try to escape, flying into the bag. Other species of birds generally do not fly out into the bag.
  • Don't try to remove the birds by opening the nestbox door--you are too likely to lose them. Once a male has escaped a nestbox trap, he will be very difficult to recapture.
  • If you have a top opening box and good reflexes, or it is night time, you may be able to quickly slip your hand in while the bird hunkers down and grab it. I've had too many escapes with this approach. I wouldn't want to end up with a snake in my hand either.
  • Some people have luck during active nesting putting a mayonnaise jar over the entrance hole and shining a flashlight in, and the birds fly into the jar. Slide the jar over the box to the edge and put the lid on.
  • If a bluebird is trapped, they generally will not fly into the net. Instead they stay on the nestbox floor. Prop the door open and leave the area so the bluebird can exit.
• Ground Trap:
  • When you put your hand in the ground trap to remove birds or refresh food and water, they will flutter excitedly, and if you're not careful, escape. Remove one bird at a time. If the door is small, cover it with your other hand while reaching in. Or hold a mesh laundry bag around the door such that any wayward bird would fly into it. Otherwise, you might devise some kind of plastic/rubber "guard" (flaps, or cut an X in it) that you can stick your hand through.
  • Don't be afraid to grasp them firmly (without crushing) by the body. Put your hand behind the head, encircling and holding their wings close to the body so they will not struggle. They may latch onto your hand with their beak, but it's just a pinch--not painful. However, you may wish to use a pair of gloves. Do not attempt to grab them by the tail as the feathers will come out.

For traps where you can lift the trap door from the outside, hold a soup can (with both ends removed, and a plastic bag held on one end with an elastic bag) over the entrance hole. The bird will fly towards the light. Slip a piece of cardboard over the open end before removing the can.

• Use lures - feathers, nesting material, grass/stick hanging out of entrance hole and/on placed below the trap box, fake/real egg inside nestbox, a small mirror in the back of the bait tray
• For inbox traps, try a different type of trap (e.g., a Huber instead of a Van Ert), and/or cover it with a bit of nesting material that doesn't interfere with the tripping mechanism.
• Remove the trap for a few days. Let nesting material accumulate, or let an egg get laid, then reinstall the trap. (You may need to remove some nesting material from the bottom so it doesn't interfere with trap trippage.)
• Temporarily disable the trap (use a paper clip or wire to keep it from tipping) until they become accustomed to it, and then remove the wire. If you are using a Van Ert, put it in upside down for a day or so so they get used to stepping on the trigger.
• Try a two hole nestbox trap where the female is in one compartment with Plexiglas in between.
• If they escaped from an inbox trap, try a ground trap.
• For ground traps, female decoys may work best. If you can use the mate, so much the better, although this does not always work. If nestlings are present, the entire nest can be place in the ground trap as the male will be highly motivated to feed his young.
• Try a night sneak or try different timing.
• Another temporary nestbox with trap placed next to the box they are using may be attractive.
• Record the call of a HOSP or Eastern Bluebird off the web (use a double male mini plug cord to connect a laptop to a small cassette player/recorder and set Windows Media Player to Repeat and come back 15 minutes later) and then play the call through ear buds (in-ear headphones) inside the box, while the player stays outside.
• This is gruesome, but one person reported success by placing the deceased and frozen female mate (in a lifelike position) inside the nestbox. A HOSP will generally not enter a nestbox that contains a HOSP adult that is obviously dead.
• If a HOSP has been trapped in a box and escaped (or even beforehand), tack a fake Black Paper Van Ert inside the nestbox after removing the HOSP nest. You can make one from felt paper used under roofing shingles. This gets them used to a black object under the entrance hole, and then you can catch them more quickly with a real trap. (Keith Kridler)

If it is not possible to trap them, you may need to resort to shooting. However, they also quickly learn to recognize a gun, so a blind may be needed. Do not look the bird in the eye.

For monitors concerned about trapping on a trail frequented by people: active control is still possible. Inbox traps are less noticeable than ground traps. If you don't own the property the nestboxes are on, be sure to ask permission to trap.

• During nestbox checks, make a note of which boxes have HOSP. Leave everything undisturbed at this point, except set up the screws for putting an inbox trap on the door later. Return at dusk or at night, approaching the box quietly from rear. Block hole with small rag or sock. Cover box with a mesh laundry bag and open the box, or open it just a crack while blocking all exits with other hand, and reach in and grab the HOSP.
• You may wish to use the Mel Bolt inbox-trap, which catches the bird in a little cage so a bag is not needed.
• If you catch a female, set the inbox trap (which no one can see externally) and check again about hour after sun up to get the male. Then remove everything (trap and nest material) from the box so it is ready for another bird.
• You can also start your monitoring route at the nestboxes you know may have a HOSP problem. If you see HOSP nesting material, set the inbox trap and continue monitoring. Then loop back around. Within 30-45 minutes you will usually capture the HOSP.
• Ground trapping in public places or commercial establishments: is not recommended. The vast majority of people do not understand the threat posed by HOSP. Even if they do, most do not think anything should be done about it. Other people who accept passive controls or removal of nests or eggs will not tolerate live trapping. Even if you educate the owner, their employees, customers or visitors might not understand. It would place them in a difficult position to have to try to explain. Since some of these places may be the equivalent of a HOSP factory, you might choose to try this anyway. If you do:
  • Either put the traps out after the establishment is closed (with permission of course - I strongly suggest you get it in writing to protect yourself
  • ) and retrieve them before they open, or place traps on the flat roofs of buildings (you will need a ladder) or another location where they are not visible to the public. Regularly empty the traps. Of couse ALWAYS leave food and water inside any ground trap.
  • Use a bicycle lock to chain the trap to a fixed object. Tightly screw shut the door to the trap or put a lock on it also, so well meaning people do not release birds.
  • You might explain that you are doing research for a bluebirding group to see how long it takes HOSP safely live trapped in one location to return to their roosting areas when released in the city (at least 10 miles away). Generally I don't advocate releasing birds in another location, as it just relocates the problem. But it may be better than nothing, and some people argue there are no native birds left in cities anyway because of introduced birds like HOSP, starlings and pigeons. Relocating birds without a permit is illegal in some states like MA or CT.
  • Leave a laminated copy of information (like the Advisory on HOSP) cable-tied to the trap explaining that the non-native House Sparrows are being trapped to prevent them from killing native birds like bluebirds.
  • Give copies of the commercial establishment advisory to the owners, with copies for employees. Ask the owner to make it clear to employees/relatives etc. that trapping has been okayed, and that they should leave the trap alone or contact you if there is a problem (like a native bird trapped) so you can walk them through it or handle it yourself.
• If you euthanize House Sparrows, don't do it in public. It can be too upsetting to people, especially if don't understand what you are doing and why. Instead, put the captured bird in a mesh bag, wrapped tightly so the bird does not struggle, or put it in a bird cage in your vehicle to deal with it later.

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A good inbox trap is a must in HOSP management, because it enables you to capture the very bird that would destroy a native nester if it were in that box.

INBOX TRAPS Types: The three commonly used types of in-box traps are: Huber-style, Gilbertson universal, and Van Ert. Most have a little metal arm that the bird lands on, which trips a lever that then covers the entrance hole. They are all inexpensive and very effective during nesting season. They are placed on or inside the nestbox entrance hole. Most have a bright orange spot that lets you see from a distance whether the trap has been tripped. It is best if no parts of the trap can be readily seen from outside the box--a savvy male might not enter otherwise. However, it is easier to catch a male in an inbox trap than a ground trap. See Paula Z's review of traps.

• I prefer the Van Ert - it consistently works well; is durable; it snaps shut securely (can't wiggle out); and is easy to place (ten second set up), remove and replace. It sits on two #10 (or #8) mounting screws you can leave in place. You will need a stubby Phillip's head screwdriver (shortest one they make) to install the screws. The trap comes with a template, or you can take the trap itself and set it in the box where you can see it will spring shut freely and block the bird's exit. For a side opening box, you can put the template on the front of the box and drill the screw holes right through the front. Screw it in so trap is flush with box front. The bottom mounting screw can be left sticking out a little as it is more of a guide to place the trap and hold it straight. (Note: in a Super Gourd, bend the plate [that the birds stand on] on the inside of the gourd, and then use a rubber band to hold the Van Ert to the plate.)
  • Van Ert is now making his next generation of traps with a removable trip wire, so you can leave it in "safe mode" when you are not able to check it, or to let HOSP get accustomed to it, and then reinstall the trip wire when you are ready to trap.
  • On rare occasions, this trap will apparently either not trip until a second bird enters, or will be pushed open by a second bird and trap two birds (sometimes a male and a female HOSP). If a HOSP is trapped inside with another native bird, the native bird will probably be killed, which is another reason to check it frequently.
• The Huber trap may work better with HOSPs who are spooked by seeing the trap mechanism (e.g., of a Van Ert trap, especially if they were previously trapped with one) and refuse to enter the box. It's a steel plate that drops down when the entering bird steps on a trigger rod. The one sold by the Martin marketplace has a single screw that stays with the trap. You reach inside the box with the trap, match the center hole up with the box entrance and screw the eye screw into the inside of the front of the box. It is a bit difficult the first time as you are making a new hole in the box, but after that it can be installed and set in a few seconds. Most Huber traps do not fit on a Peterson box, slot of PVC-pipe box. It is more likely to prematurely trip (e.g., in response to wind) than a Van Ert inbox trap. I have also had a bird in the box and it DIDN'T trip.
• The Bolt "H" type trap works best with front opening nestboxes that are hinged at the bottom, or top opening boxes. It contains the trapped bird inside a little cage with a door on it. You open the box and can immediately see what you have in the trap. No bag is needed, so it makes for easy, quick removal. This is Maynard Summer's favorite inbox trap.
• Gilbertson makes a small hang-on "universal" trap that uses a piece of steel tape measure. It works on all box styles except a slot and Gilwood.
• The Peterson sparrow trap fits a Peterson box.
• Jack Finch makes another coil spring sparrow trap that pivots up to close off the entrance hole. This might work with House Sparrows scared of of the Van Ert trap.
• DIY: You can build your own inbox trap.
  • Bauldry Trap
  • Bolt Trap
  • Gilbertson Trap (screw or hang on any box style except slot - made with a tape measure.)
  • Gruenke 10 Minute Trap (This is a good emergency nestbox trap)
  • Huber Trap
  • Peterson Trap
• Slot boxes: A Stutchbury trap can be used in slot boxes. Tilt the bottom of the nestbox forward if possible. Cut a piece of plexiglas, sheet metal or plastic 0.5" narrower than the width of the slot entrance. Attach a large washer/quarter as a weight to the bottom edge of the trap. Using duct/masking tape stapled/tacked to the roof, hang the trap down just inside the entrance (blocking the entrance), with the weight on the side facing the box interior. Prop the trap up with a piece of straw, which the HOSP should knock over when entering, releasing the trap.

• For a two hole box, put tape/a cork/rubber stopper (can be painted to match the box - available at a hardware store) in one of the hole and use an inbox trap on the other hole. In wider boxes, you can mount two traps, and put a plexiglas divider in the middle, which enables you to trap both the male and the female.
• Box with large vents: If the nestbox has vents large enough for a trapped HOSP to exit, be sure to plug them up during trapping.
• Nestboxes with built-in traps: There are also several nestboxes made with built-in traps. These traps can be placed next to, or used to replace a box that HOSP have shown interest in. You can drill a 1 1/8" hole in the the box just in case a chickadee or wren goes inside, so it can escape. If HOSP are using another box and you place this one nearby, take the nesting material out of the other box and put it in the trap box. (Make sure it is shallow enough so it doesn't interfere with the trigger mechanism.)
  • Van Ert makes a cedar nestbox "Urban sparrow trap" with a built in steel trap. The hole is 1 3/8 ", which allows HOSP, but not MOST bluebirds, to enter. You can buy a portable stand for it. It's a neat concept, but I have not caught a lot of HOSP with it.
  • PMCA makes a nestbox that is a starling/HOSP trap. It is expensive and heavy, it is difficult to remove birds, and less effective than the Van Ert / Huber / Gilbertson traps, but it does have an escape hole for chickadees and wrens. (I've had wrens nest in mine even with the main entrance trap tripped closed.)
  • A 6" deep slot box with a 1" entrance (to exclude bluebirds) can be used as a trap box, fitted with a Stutchbury trap that is 4" wide.
  • There is a separate nest-trap box that can be placed over the entrance of a regular nestbox.
  • 2 Hole Huber Style: This nestbox has 2 holes, with 2 holding chambers inside, separated by Plexiglas for trapping both male and female HOSPs. The holes are 1 3/8" to prevent bluebird entry. When one HOSP is trapped and the entrance hole blocked, the mate should come to investigate. To look inside, they go in the other entrance hole, and are trapped. Note: John Schuster, who sells a "Gable" version of this trap at Wild Wing Co., feels that replacing a regular box with this nestbox trap is most effective when the original box is also two-holed. His trap box also has a circular door (covered with 1/2" wire attached to the main door) that slides up so you can look inside to see what has been captured.
  • If you use one of your own nestboxes as a trap box, you can use a removable roof with a piece of hardware cloth stapled underneath it (bend the sides of the cloth down over the box) so you can check to see what type of bird has been caught.
  • Tipping Can Trap DIY instructions (similar to an S&S Starling Trap, but modified for HOSP) can be found at Chuck Abare's A Birds Home website.

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  INBOX TRAPPING TIPS
  
• Hole: If you have a box used exclusively for trapping HOSP, consider putting a plate over the hole to reduce the entrance to 1.25 inches. This will prevent most blues from entering. Bluebirds - especially males - WILL check out other boxes, even when they have an active nest going elsewhere. You still need to monitor hourly, as Tree Swallows, chickadees and other