FAQs

1. What's the difference between a birdhouse and a nest box?
2. How can I tell if a raccoon has raided my box?
3. How can I discourage predators like raccoons from raiding my nest box?
4. What should I do if House Wrens nest in a box that I put up for bluebirds?
5. If I disturb a bird's nest, won't that cause the mother bird to abandon it?
6. What do I do with the nest after the birds have fledged?
7. I have always had Bluebirds nesting in my boxes. This year I found eggs, but no parents. Why?
8. I checked my nest box, and found dead babies. Why?
9. I have birds nesting, and the nests are infested with bugs. How can I get rid of them?
10. I have a blowfly problem, what can I do?
11. Why is this bluebird attacking my window?
12.  What do I do with the nest after the birds have fledged?

Q1.  What's the difference between a birdhouse and a nest box?

A: Nothing. Nest box is another term for birdhouse.
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Q2: How can I tell if a raccoon has raided my box?

A: This is a common question we receive during the breeding season. The telltale sign of a marauding raccoon is a totally disheveled nest: eggs or chicks, if they were present in the nest, may be dumped to the bottom of the box, or they may be gone altogether. Nest material is pulled up from the nest and many times is hanging out of the entrance hole. Sometimes nest material is on the ground under the nest box. Raccoons tend to either sit on the roof of the box or hang on the side of the box and reach in through the entrance hole. They pull at anything they can reach whether it be nest material, eggs, or nestlings. Once raccoons make a habit of raiding your nest boxes, they are quite capable of wiping out many broods in one night.
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Q3: How can I discourage predators like raccoons from raiding my nest boxes?

A: The best predator deterrent is a combination of a smooth, slippery pole and a predator guard or baffle. Trees, wooden fence posts, and fence posts intended for wire fence won’t even slow down most predators, as all of these provide marvelous toe-holds for climbers, or rough surfaces for snakes. Galvanized pipe or PVC pipe are both slippery, smooth surfaces that most predators will have difficulty climbing. Adding a predator guard or baffle will stop all but the most acrobatic predators. Make sure your nest box is not set up next to a tree or similar object that predators can use as launch pads.
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Q4: What should I do if House Wrens nest in a box I put up for bluebirds?

A: House Wrens are commonly implicated in the puncturing of eggs of other cavity-nesting species. For this reason, some nest box landlords prefer not to play host to House Wrens. If you prefer not to attract House Wrens, make sure your nest boxes are far from shrubs or woods. The more open the site, the better. Please remember that it is illegal and unethical to disturb the nest or eggs of any native bird species, including House Wrens. The only species that are not protected by law are the non-native European Starling and House (English) Sparrow
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Q5: If I disturb a bird's nest, won't that cause the mother bird to abandon it?

A: Careful, sensible monitoring does not harm the birds and can add volumes to our knowledge of the nest box inhabitants. People are usually surprised to learn that you can peek into birdhouses (nest boxes) on a regular basis without harming the birds. The myth about birds smelling your scent on the box, nest, or eggs is exactly that: a myth. Songbirds generally have a poorly developed sense of smell, and careful nest box monitoring rarely leads to nest abandonment. If you’ve never had the pleasure of being a "nest box landlord," you’re in for a treat. The more you can learn about the biology of your nest box occupants, the more rewarding your birdhouse monitoring will be.
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Q6: What do I do with the nest after the birds are through fledging?

A: Typically, old nest material is removed when the breeding season is over. New evidence suggests that this may not be the best procedure.  After nesting season is complete, some people elect to seal off their birdhouses to prevent unwanted winter tenants. Some people render the boxes unusable by propping the door open. Others leave the boxes as they are and allow them to be used as roosting places for birds, mice, or squirrels. If your nest is soiled with fecal matter, we recommend removing the nest and cleaning the nest box out with a solution of 1 part bleach to 10 parts water. If the nest is not soiled, you can choose to leave the nest in place or remove it altogether.
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Q7: I have always had Bluebirds nesting in my boxes. This year I found eggs, but no parents. Why?

A: If you find a nest with eggs and no parents, first verify that the nest is actually abandoned.  The incubating adult may leave the nest for periods of up to 15 minutes to feed and/or let the eggs slightly cool. Or, while many songbirds do start to incubate the day before or the day the last egg is laid, sometimes the parents make exceptions. For example, Tree Swallows may wait up to a week to start incubating a clutch of eggs. Finding such a nest may give the appearance of abandonment, when in reality this is not the case. For most birds, eggs will remain viable for up to two weeks after being laid and before being incubated, so as a rule of thumb, you should wait at least this long before discarding unincubated eggs. Remember that it is illegal to remove nests and eggs from active nest boxes, so do not remove nesting materials until you are certain the nest is not being used.

Parents may abandon a nest for several reasons. They may be captured by a predator, or collide with a window or passing car. If one parent disappears, the remaining parent may abandon the nest, search for a new mate and start over. A competing individual may drive them off of their territory, or a competing species may usurp their nest box. A severely traumatic event, such as a predator investigating the nest box for too long, or an infestation of insects, could also cause the parents to leave.
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Q8: I checked my nest box, and found dead babies. Why?

A: Several factors can lead to this situation. Parents may abandon a nest for the reasons described above (see FAQ #10). Species competing for the nest box may usurp a cavity with an active nest. The non-native House Sparrow (Passer domesticus) is infamous for killing nestlings and occasionally an adult bird. Severe parasite infestations could render the young so weak they cannot survive. Other causes of death include genetic disorders and chemical poisoning which are both difficult to diagnose.
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Q9: I have birds nesting, and the nests are infested with bugs. How can I get rid of them?

A: Several insects will use birdhouses to nest, including wasps, earwigs, and blowflies (which are nestling parasites). If you find wasps are building a nest on the inside roof of your nest box, use the end of a pencil to knock off the nest while wearing a pair of gloves to protect you from wasp stings. Be careful when removing wasps! If the wasps repeatedly build in your nest box, coat the inside of the roof with a non-toxic substance like Vaseline or Ivory soap: this will prevent them from building. If you have blowflies, read below (FAQ #13). Many other insects, like earwigs, pose no threat to the nestlings (earwigs are omnivorous, eating mostly decaying plant parts), and can be physically removed by brushing them out.

If you have saved an old nest from a previous nesting attempt, you can "exchange" the nest. Simply place the eggs or nestlings in the surrogate nest, remove all of the contents of the nest box, and place the "new" nest with offspring back in the box. Do not use an insecticide or any other chemicals in the nest box! Nestlings are extremely susceptible to toxins, and the exposure could be fatal or interfere with normal development.
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Q10: I have a blowfly problem, what can I do?

A: According to Dr. Terry Whitworth, studies show that low to moderate blowfly infestations have little effect on the nestlings. A severe infestation (10 or more actively feeding larvae per nestling) can be dealt with by physically removing the larvae. Alternatively, exchange the nest for an old, uninfested nest.

Q11: Why is this bluebird attacking my window?

A: Bluebirds, especially males, are very territorial during the breeding season, vigorously defending their territory from other bluebirds. When pecking at the window a bluebird may not realize he is attacking his own reflection, not a bluebird encroaching on his territory. The territorial response may be so strong the bird will attack his reflection without stopping to feed. This behavior should only last through the nesting cycle, and is preventable during this period.

To dissuade the bird from attacking your window, break up his reflection by hanging mylar strips or streamers from the top of the window, or block his reflection completely by mounting cardboard on or soaping up the outside of the window.
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Q12:What do I do with the nest after the birds have fledged?

A: During the breeding season, you can leave the nesting material in the box – the parents may decide to raise another brood. At the end of the season, you can remove the nesting material and scrub the inside with a mild detergent and water. You can leave your box up over the winter and allow it to be used as a roosting place for birds, mice, or squirrels.