Bluebird and Small Cavity Nester Conservation
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Sparrow Spookers

Quick Tip: Make a spooker so strips of mylar will flutter over the top of the nestbox (Design #2 or #4 recommended). Install the spooker immediately after the first egg is laid to deter House Sparrow attacks. Remove it (and the used nest) immediately after fledging to encourage another brood, and to avoid HOSP becoming accustomed to it.

NOTE: If you have two boxes, and HOSP are building in one, and bluebirds in the other, either trap the HOSP, or addle the HOSP eggs, or wait until the first bluebird egg and spooker installation to start removing HOSP nests, to prevent HOSP from moving to the bluebird box before you can protect them.

Sparrow spookers are usually extremely effective in deterring House Sparrows (HOSP) from entering a bluebird nestbox to attack eggs, nestlings or incubating adults. You can't watch the nest 24/7, but a sparrow spooker will protect it for you. It acts like a sort of force field. It is literally a life saver. They are used on active nests of native birds in conjuction with other HOSP control measures. Sparrow spookers are one of the few passive HOSP controls that really work. Nothing is guaranteed 100% effective against House Sparrows, but these come close if properly installed after the first egg and removed after fledging. (Note: If the only control measures you take are are removing HOSP nests and eggs, it is POSSIBLE that such actions can stimulate extreme aggression and a HOSP may overcome its fear of the spooker. I had this happen on one occasion on an experimental trail where I was not trapping HOSP.)

Timing: Ideally, put the sparrow spooker up after egg laying begins, but before incubation begins to protect unattended eggs, and give the parents more time to accept the addition so incubation is not interrupted (eggs can chill). If you put it up while eggs are still being laid (they lay one a day, and incubation does not begin until a full clutch), you will have confirmation (with a new egg the next day) that the spooker has been accepted. See discussion on why you should wait till the first egg.

If the babies have already hatched and HOSP are in the area, I would recommend putting up a spooker later rather than not all. But try to do it in the morning when it is not too windy, and observe for up to an hour to verify acceptance. (The female may accept it more quickly than the male - fear of new things tends to be individual and species-dependent.)

If you have two boxes, and HOSP are building in one, and bluebirds in the other, either trap the HOSP, or wait until the first bluebird egg and spooker installation to start removing HOSP nests, to prevent HOSP from moving to the bluebird box before you can protect them.

Remove the spooker as soon as the babies fledge to encourage another brood AND to avoid HOSP getting used to it, which will destroy the effectiveness of one of the best HOSP-deterrents we have.

Design: Several designs are shown below, but all have material that flaps over the roof (barely brushing it - i.e., when it's not windy they touch the top of the roof), near the entrance hole. For some reason, like monofilament, this "spooks" HOSP, but does not discourage bluebirds from entering the box once they have started laying. In fact, after awhile blues may even perch on the spooker.

Sparrow Spooker made by Sparrowtraps.net
Sparrow Spooker side view.  By sparrowtraps.net

See instructions below on how to make a spooker.

A ready-made, weather-resistant Sparrow Spooker is now commercially available from Sparrowtraps.net. This spooker is readily mounted on any style box. The height and spread of the "V" shape are adjustable. it comes with two mounting brackets so you pop it on the box that is "chosen" as soon as the first egg is laid. It comes with a roll of Mylar tape that you can cut to size and clip on the horizontal bars. Bluebird landlords were involved in its design. To keep it from spinning, put a little duct tape around the rod where it goes through the white holder.

Photos courtesy of Sparrowtraps.net.

Design #1 using "T" shape. I definitely recommend modifying this so the mylar hangs down from something parallel to the roof. Design #2 (typical) with dowels in a "V" shape, and mylar flapping above and near entrance hole. THIS IS MY FAVORITE SPOOKER, and HAS NOT BEEN DEFEATED TO MY KNOWLEDGE.
Sparrow Spooker Drawing by Yvonne Domings Sparrow spooker drawing by Bet Zimmerman
Design #3 using flagging material on a stick or pole. Streamers may not consistently get close enough to entrance hole so this design may be less effective in my opinion. NOT RECOMMENDED as it sometimes fails - only shown here for historical purposes as it was the original concept. Design #4 for Gilbertson Box. Long, thin piece of scrap wood/dowel (tied to pole with plastic cable tie), with plastic elbow and a short piece of lightweight metal tubing jammed down over the dowel.
Sparrow Deterrent by Lillian Lund-FilesNOT RECOMMENDED. Not as effective as designs where streamers brush the roof and hang from something parallel to the roof. Sparrow spooker.  Photo by C.Layton
Design #5. Tinsel wands used as party favors or children's toys can also be used as sparrow spookers. Tape it to the box post, above the box. (Rose Bragg of the Bluebird Restoration Society of Wisconsin) If necessary, trim the tinsel so it just brushes the roof. Design #4 on NABS-style box with plumber's elbow and PVC pipe. (Note: I think the mylar should be on top of the roof, barely brushing it, so it moves readily in the wind, and over the roof itself. This one is probably taller than it needs to be.)
Temporary sparrow spooker.  Photo by Bet ZimmermanTemporary spooker made out of cut up foil popcorn bag, duct tape, coffee stirrers and sticks. It worked! Sparrow spooker. C.LaytonAnother view of Design #4, made with PVC.
Materials: Sparrow spookers are not only effective, they are cheap to make.
  • One vertical piece about 12" long. Vertical piece can be made from a yardstick, dowel, black plumbing hose, or a piece of plastic pipe.
  • One to three horizontal pieces that are as long as the roof. The same materials can be used for horizontal pieces. Chopsticks (from Chinese restaurants) also work well.
  • Strips of flexible, reflective material - ideally mylar. (not transparent or translucent).
    • Strips are often 1/2" x 6". If you're not sure how long they will need to be once the spooker is installed, leave them long and cut them with scissors after installation. If the strips are too long, they may not hold up under windy conditions.
      • Buy mylar (shiny, silvery material) signs (e.g., Happy Birthday banners) from a party supply/Dollar Store/Wal-Mart.
      • Pieces of mylar balloons tend to curl up. The mylar used in banners is thicker, you can make the strips as long as needed, and there is less waste.
      • A Coleman Emergency Blanket (from Wal-Mart or Target) is also made of mylar, and only costs several dollars.
      • C. Layton of the Bluebird Nut Cafe made two years' worth of strips from one blue foil bag that Wal-Mart potato chips come in (after the chips were consumed:-).
      • Aluminum foil does not work as well (doesn't flap, falls off), but can be used in a pinch, as can tree flagging material, which does not last.
    • The strips may be attached to the horizontal piece with a glue gun, duct tape, or staples. Lately I've been using a long piece of duct tape folded over the horizontal dowels as shown in the temporary spooker above (don't leave anything sticky out that a perching bird might get stuck to.)
  • A means to attach the device to the nestbox - e.g., screw, hose clamp, duct tape, cable tie, etc.
    spooker configuration

Instructions:

  1. Drill hole(s) the diameter of the horizontal pieces into the vertical piece of wood (or a 1" piece of waste drain hose - fits well if box is mounted on a metal conduit pipe).
    • Design #1 diagram uses two dowels in a "T" configuration. In Design #2, the dowels stick out over the nestbox roof in the shape of a "V," and extend to the front edge of the roof. The original Design #3 uses a vertical piece only.
    • Design#4 relies on an "L" shaped plastic plumber's elbow to connect horizontal and vertical pieces.
    • Whatever you use, it shouldn't be too heavy.
  2. Glue the dowels into the wood strip for Designs #1 and 2. Don't use wood that is too heavy.
  3. Attach the mylar strips at even intervals to the horizontal pieces (3 or 4 per dowel) so they hang down loosely over the roof, just brushing the roof. If the strips are too long and hang over the entrance hole, the bluebirds may not like it, although some folks use that set up.
    • If you're not sure how long to make them, cut them extra long and then after mounting the spooker on the box, trim so they just brush the roof.
    • Try a staple gun for attaching.
    • If you use duct tape, it may deteriorate in rain. You can lay the duct tape out lengthwise, draping it over the horizontal piece, and then sealing it to itself. Be sure no sticky parts are exposed as birds may perch on it.
    • If you use hot glue, it may melt in the sun, so put the glue on the inside where the mylar touches the dowel, or also use duct tape for added adherence.
    • Another option (shown in Design #1) is to drill holes in the vertical pieces, and then pull the mylar through the hole and knot it.
  4. Mount the sparrow spooker to the back of the bluebird house so that there is a distance of about 8" between the roof line and the top of the device. This will allow the mylar strips to blow freely in the wind. The strips should almost touch the roof of the house. In order to avoid addling eggs, do not shake the box during installation (e.g., avoid drilling or remove nest during drilling.) Be careful not to split a wooden roof when you attach a screw (pre-drilling is a good idea here but see note above.) Connection options include:
    • a hose clamp on the pole if it sticks up above the roof, for easy removal after fledging
    • as shown in Design #1
    • with locking cable ties as shown in Design #4)
    • If the spooker wants to fall over, you can put a nail/screw on either side of it to hold it upright, or use two screws one over the other.
  5. If you have a bluebird trail in a public location, you might want to thumbtack a little laminated tag onto the side of nestboxes with Sparrow Spookers installed, to explain to interested public what the mylar contraption is.  It might encourage them to try one out. (Thanks to Paula Ziebarth for this idea.)

Acceptance: Different species and different individuals of the same species behave different, and may react differently to anything noticeably new. By putting the spooker up after the first egg is laid (usually before 1 p.m.), you will have confirmation of acceptance (and will not have to worry about interrupting incubation), as long as a new egg is laid the next day. You will also be protecting the nest while it is unoccupied, since the female does not begin incubating the eggs until she finishes laying all her eggs.

Sparrow Spooker.  Photo by Pam from NJ

If desired, observe the box after installation. In my experience, the female usually accepts it almost immediately--it may take the male 10-30 minutes. Males have been seen grabbing the end of a piece of mylar and shaking it or pulling on it right after installation.

It would be unusual for a spooker not to be accepted within an hour or two. (I have heard of one instance where it was NOT accepted by the female, and she only returned to the box after the spooker was removed. That is why observation is useful.)

Avoid installing the spooker when it is very windy, as this may affect acceptance. If they don't seem to accept it right away, leave the spooker up but take a rubber band and bunch the streamers to the top post out of the way. Then let one or more of the streamers down every day to desensitize them.

Can I put the spooker up before an egg is laid? Some people have so many problems with House Sparrows that they want to put a spooker up BEFORE an egg is laid. I do not really recommend it for these reasons:

  1. HOSP could become accustomed to it, and this very useful tool could lose its effectiveness! You might end up training HOSP to overcome their fear of the best HOSP deterrent there is so far. (I heard at least one report where a spooker was put up during nestbuilding and a pair of HOSP did overcome their fear of it.)
  2. It could possibly deter bluebirds (or other native birds) from using the box, since they are not as committed as they are when they have laid an egg.

Instead, I recommend monofilament (which reduces HOSP interest in a box if put up before the male 'bonds' with the box) and other methods (passive and active) in the interim.

One person did report putting sparrow spookers on two nestboxes early - one during bluebird nest building (before egg was laid), and one before Tree Swallows occupied a box (the previous swallow occupant was killed by HOSP). In both cases, the bluebirds and Tree Swallows did accept the "early" spooker and went on to successfully nest. More data is needed on this practice. Another person left one up after fledging, and the bluebirds went on to build a second nest. However, see concerns above.

We really do not know why the spooker or the magic halo deter HOSP and not other birds. Perhaps as seed eaters, their vision is not as good as birds that are predominantly insect eaters. When placed on a mealworm feeder, a spooker was not accepted by blues. A Magic Halo is a better choice for a FEEDER - it is NOT intended for use on a nestbox.

If the spooker is on a box in a public place, you might want to thumbtack or staple a laminated message to the box for educational purposes: "The mylar "sparrow spooker" above this box is meant to keep nonnative House Sparrows from killing the Tree Swallow adults/eggs/nestlings that occupy this nest box."

Failures: I have heard of the following instances of spookers failing:

  • One with Design #3
  • One where non-iridescent material was used
  • One with unknown design
  • One with Design #2, after the male bluebird disappeared. Failure may have been associated with particularly aggressive male HOSP, and mylar curling up and thus not extending or fluttering properly.
  • One with a standard, recommended design - a female HOSP entered the box on several occasions (but did not harm nestlings)
  • Two with standard design, while HOSP nests and eggs were being removed in neighboring boxes. See discussion of HOSP revenge syndrome. Instead of removing nests and eggs, addle the HOSP eggs so they are nonviable and return them to the nest. (This will not help with single males.) The safest, most effective solution is to trap both the male and the female to completely eliminate the possibility of an attack.
  • One where the spooker was not removed between first and second nestings, and the strands deteriorated and no longer brushed the nestbox roof.

A Spring 1995 issue of Sialia contained a report that Wayne Davis and Beth Blankenship experimented with four streamers made of plastic flagging, hung from the front of the roof of slot boxes. With this set up, the bird would have to go in between the flagging to enter the box. No deterrent effect was observed either on bluebirds or HOSP.

Note that Sparrow Spookers do NOT deter House Wrens, which may also peck and remove eggs and very young nestlings.

Other Species:

  • Several people have had Tree Swallows accept Design #1 and #4. They may balk. I tried Design #2 on a pair of TRES in CT and it was not accepted after 15 minutes so I removed it (it was very windy when I tried). See recommendation on wind. Little information is available about acceptance of sparrow spookers by other cavity-nesters, or pre-egg laying.
  • It would be reasonable to expect that titmice and chickadees, which are more sensitive to monitoring, might take issue to a spooker. Anne-Marie Palermino succesfully used a spooker on a chickadee nest, although hole restrictor (smaller than 1.25" diameter) may be a better choice for these birds.
  • Claudia Daigle successfully used one on a House Finch nest.
  • Pam Stenner used a variation on an Ash Throated Flycatcher nest. She said "they are so secretive and shy that I wasn't sure how they would take to a spooker. So I put up a spooker "frame" --a piece of wood that I could hang the mylar streamers from, before they even started building a nest. After they had laid a couple of eggs, I hung just one mylar streamer far away from the entrance hole. When they were okay with that, I added more one at a time--each one closer to the entrance hole." They accepted it.

A sparrow spooker is an invaluable tool to protect nesting bluebirds. However, nothing besides trapping and elimination is foolproof. To effectively manage HOSPs, I recommend using a combination of passive and active control techniques.

Sources and Acknowledgements:


I used to lose the majority of Bluebird and Tree Swallow eggs and young to HOSP, even with an active trapping program. Adding Sparrow Spookers resulted in 100% success rate last year.
- Mark, Wildlife Gardeners, 2009

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