Georgann Schmalz
Birding Adventures, Inc.

GENERAL INFORMATION ABOUT BIRDS THAT USE NEST BOXES

Over thirty species of North American birds nest in cavities.  Some of these birds, like woodpeckers, can excavate their own cavities. Other birds, mostly songbirds, rely on previously used holes or naturally occurring cavities, crevices, or tunnels.

The size of the bird house, the diameter of its entrance hole, and site placement will determine which species uses the box.  Seven species of birds that nest in the southeastern U.S. will use birdhouses:  Carolina Wrens, Tufted Titmice, Carolina Chickadees, Brown-headed and White-breasted Nuthatches, Eastern Bluebirds, House Finches, and House Wrens.

Carolina Wrens (Thryothorus ludovicianus) are feisty small brown birds that nervously dart about often with their tail pointing straight upwards.  Wrens are friendly and will nest in any suitable cavities, nooks or crannies around buildings.  They often prefer unusual places such as hanging flower baskets, wreaths hanging on doors, or even paper bags and boxes left in an open garage. Since they are opportunistic, they are not fussy about the dimensions or the placement of your bird box.

The small gray Tufted Titmouse (Baeolophus bicolor) uses abandoned woodpecker holes and natural cavities in tree trunks or limbs. However, they will readily come to your bird box.  In fact, theyare often the first birds to investigate it and move in.  They prefer a somewhat wooded area with the box approximately 5 feet off theground, securely fastened to a tree trunk.

Carolina Chickadees (Poecile carolinensis) share similar requirementsas Tufted Titmice.  In addition, both species are easily attracted to sunflower seed and bird feeders.  They construct their nests of soft materials, moss, and fuzz.  Small gathered pieces of moss, soft dog or cat hairs, or 2 inch segments of yarn may be placed near a box.  You will know if they used your proffered items in the fall when you remove and discard the old nestf rom the box.

Brown-headed Nuthatches (Sitta pusilla) and White-breasted Nuthatches (Sitta carolinensis ) can be difficult birds to attract to a man-made bird house.  They prefer to nest as high as 30 feet. You can increase your chances by placing your box as high aspossible.  Nuthatches are a delight to watch as they creep up and down tree trunks grabbing insects from under the edges of the tree bark.

Of all the birdsthat people wish to attract to a bird box, the Eastern Bluebird ( Sialia sialis) ranks perhaps the highest.  Bluebirds experienced a severe population decline from the 1930`s to the 1970`s.  Being insectivores, these birds were eating the pesticides (notably DDT) used to kill insects.  With the destruction of woodlands and removal of dead trees, they were further pressured by loss of nesting cavities.  Although we still use pesticides that often threaten wildlife, the practice of constructing bluebird trails and the use of bird boxes has returned the Eastern Bluebird to stable populations.  Bluebirds prefer a box that has its back to the woods and faces a large open area.  Their entrance hole should be l-l/2 inches.  European Starlings and House Sparrows will try to nest in bluebird boxes.  Careful monitoring and removal of starling and sparrow nests will insure that your bluebirds will successfully nest in your box.

House Finches (Carpodacus mexicanus) are not native to the eastern U.S. Some were captured from the western U.S. in the 1940`s and carried to New York to be sold as caged birds.  The Endangered Species Act prohibits native birds to be sold, so the few dozen House Finches were promptly releasedin the northeast.  Over the past fifty years, these very opportunistic birds have reproduced and traveled as far south as Florida.  Their western travel has placed them side-by-side witht heir naturally occurring western relatives.  Many people fear that the House Finch will displace Purple Finches in the southeast.  However, we see fewer Purple Finches in the winter months probably due more to milder winter temperatures than to House Finch competition.  House Finch nesting is very similar to that of Carolina Wrens.  What works for the wrens will probably satisfy the finches.  In very recent years House Finch populations have declined probably due to a rapidly spreading eye infection.

House wrens (Troglodytes aedon) look much like Carolina Wrens but withou tthe white eyeline.  Known to nest readily in boxes, they actually prefer an entrance hole that is elliptical.  House Wrens use small 3 inch sticks in their nest and can more easily fit these through an elongated entrance hole rather than a round hole  As with most other birds previously discussed above, house wrens prefer their box to be placed about 5 feet above the ground, facing an open area.

PLACEMENT OF YOUR BIRD BOX

In the southeast,  cavity nesting birds begin searching for suitable nest sites as early    as February.  If you removed your box during the winter months,  place it out again by early February.  Watch for activity around  the box.  Usually the male of the species inspects the house first  and then tries to “sell” it to his mate.  In many cases, she will  not care for the first box he shows her.  Having two or more boxes for her to choose from will increase your chances of successful nesting.  However, you will not get more than one pair of the same species nesting close together.  For example, Eastern Bluebirds  prefer to nest 75-100 yards apart.

As discussed  above, placement of the box may be more important than dimensions and  entrance hole size.  Some species prefer an open area (bluebirds)  while other are more  likely to choose a box in a wooded lot (titmice, chickadees,    nuthatches).  If your nest box is not successful by mid-May, try  moving it to another site.  Don`t give up–birds may take a year or two to find and choose your box.

When attaching  your box to a tree trunk or post, nail it securely at the top and  bottom.  Birds rarely nest in boxes that swing or move  around.  The direction in which the box faces doesn`t matter as long as it is sheltered from the prevailing storm winds that come from  the west.  Your box should be hung  five feet above the ground in order to attract the most species and  make  it easy to maintain.

MAINTENANCE OF YOUR BIRD BOX

If your bird box ismade of cypress, cedar or redwood it is naturally rot-resistant andwill not need further treatment.  Pine, fir or spruce boxes can be painted on the outsideif desired.  (Do not paint the inside of the box.)  A brown or neutral colored exterior paint can be used.  An alternative to painting it is to apply several coats of raw linseed oil to the box.

Do not consider putting up a bird box unless you are committed to making it a safe place for birds to nest.  This includes not only cleaning the box  but also checking it while the birds are nesting in it. Check the box to remove broken eggs or dead nestlings.  If House Sparrows or European Starlings begin to nest in the box, open the top and remove their nest materials so that other birds can nest.  Do not remove other birds` nests since it is against the law.  Put out more boxes if you want.

Approaching the box will not chase the parent birds away if it is done infrequently.  Do not check the box the day before the nestlings are due to fledge.  Accidently flushing them out of the box even one day early may leave them not quite as prepared as they should be for the outside world.   It is not true that touching the nest or eggs will cause the parents to abandon the nest.  The trail that you leave behind, however, may attract predators such raccoons, snakes,or mice to the nest.  Try approaching the box from one direction and leaving by another, thereby avoiding a dead-end trail to the nest.  To safe guard your box from tree-climbing predators, place at wo foot piece of aluminum flashing around the tree below the box.

During the nesting season, many people remove the nest materials from the box as soon as the baby birds have fledged.  Although It is not necessary to do so, removing the old nest may induce the birds to use it more than one time during the summer.  However, the old nest should be removed at the end of the nesting season.

Thoroughly clean your box after the nesting season in October.  Never use insecticides to clean your box.  Mites can be controlled by using a pyrethrum based powder.  Since bird houses may become infested with wasps and hornets, you may want to remove the box from the tree and store iti n a dry safe place throughout the fall and winter months.