Homes for Birds

1. INTRODUCTION
2. BIRDS YOU CAN ATTRACT TO NEST BOXES
   • Bluebirds
     
   • Robins
     
   • Chickadees, Nuthatches, and Titmice
     
   • Brown Creepers and Prothonotary Warblers
     
   • Wrens
     
   • Tree and Violet-green Swallows
     
   • Barn Swallows and Phoebes
     
   • Purple Martins
     
   • Flycatchers
     
   • Woodpeckers
     
   • Owls
     
3. SELECTING A HOUSE
4. MATERIALS
5. DESIGN
   • Table of Nest Box Dimensions
     
   • Ventilation
     
   • Drainage
     
   • Entrance Hole
     
   • Accessibility
     
   • Limiting Predator Access
     
6. BIRD HOUSE PLACEMENT
7. PROTECTION FROM PREDATORS
   • Cats
     
   • Dogs
     
   • Squirrels
     
   • Raccoons and Opossums
     
   • Snakes
     
   • House Sparrows and Starlings
     
   • House Wrens
     
   • Insects
     
8. PROTECTING BIRD HABITAT
9. SUGGESTED READING

INTRODUCTION

Bird watching is one of the fastest growing hobbies in the country. It's easy to understand why. Birds are fun to watch.

And you can watch them just about everywhere. The most convenient place to start is right in your own backyard. All it takes to get their attention is water, food, and a place to build a nest.

This publication is designed to help you build or buy suitable homes--more correctly, nesting boxes--for birds. Your success in attracting birds will depend on what you know about birds and birdhouse design. This booklet tells you what you need to know to get started:

• which birds nest in houses
• basics of bird-house construction
• proper placement
• good maintenance
• how to deal with predators
• monitoring.

BIRDS YOU CAN ATTRACT TO NEST BOXES

More than two dozen North American birds will nest in bird houses. The following descriptions will help you determine which birds might visit your neighborhood.

Bluebirds

Bluebirds have problems with other animals too. The easiest way to discourage predatory cats, snakes, raccoons, and chipmunks is to mount the house on a metal pole, or use a metal predator guard on a wood post.

Robins

Put chickadee houses at eye level. Hang them from limbs or secure them to tree trunks. The entrance hole should be 1-1/8" to attract chickadees yet exclude house sparrows.

Anchor houses for hatches on tree trunks five to six feet off the ground.

You can encourage these birds to stay in your yard by continuing to fill your suet and peanut feeders through the summer.

Brown Creepers and Prothonotary Warblers

Wrens are notorious for filling up any conceivable nest cavity with twigs, regardless of whether they use the nest. Since male house wrens build several nests for the female to choose from, hang several nest boxes at eye level on partly sunlit tree limbs. Wrens are sociable and will accept nest boxes quite close to your house.

Tree and Violet-green Swallows

Violet-green swallows nest in forested mountains of the west; boxes placed on large trees in a semi-open woodland will attract them.

Barn Swallows and Phoebes

Mosquitoes are most active after sunset. If you want to rid your yard of mosquitoes, put up a bat roosting box. One bat can eat thousands of mosquitoes a night.

But don't cross martins off your prospective tenant list because they don't live up to their "bug zapping" reputation. If you need a reason for attracting them, these gregarious swallows put on a show that's better than any television soap opera.

You have the best chance of attracting martins if you put a house on the edge of a pond or river, surrounded by a field or lawn. Martins need a radius of about 40 feet of unobstructed flying space around their houses. A convenient wire nearby gives them a place to perch in sociable groups.

Martins nest in groups, so you'll need a house with a minimum of four large rooms -- 6 or more inches on all sides, with a 2-1/4 inch entrance hole about an inch and a half above the floor.

Ventilation and drainage are critical factors in martin house design. Porches, railings, porch dividers and supplemental roof perches, like a TV antenna, will make any house more appealing.

Gourds may also be made into houses by making an entrance hole and providing drainage. If you use gourds, it's not necessary to add railings and perches. Adult martins will perch on the wire used to hang the houses.

Before you decide on a house, take the time to think about what kind of pole you're going to put it on. Martins will occupy a house that's between ten and twenty feet off the ground. Some poles are less cumbersome than others.

Gourd houses are the easiest to set up. You can string them:

• from a wire between two poles
• from a sectional aluminum pole
• on pulleys mounted to cross-bar high up on a pole.

These flycatchers may nest in a bird house if it's placed about ten feet up in a tree in an orchard or at the edge of a field or stream.

Woodpeckers

For best results, place the box high up on a tree trunk exposed to direct sunlight.

Owls

Barn owls are best known for selecting nesting sites near farms. Where trees are sparse, these birds will nest in church steeples, silos, and barns. If you live near a farm or a golf course, try fastening a nest box about 15 feet up on a tree trunk.

Screech owls prefer abandoned woodpecker holes at the edge of a field or neglected orchard. They will readily take to a boxes lined with an inch or two of wood shavings. If you clean the box out in late spring after the young owls have fledged, you may attract a second tenant--a kestrel. Trees isolated from larger tracts of woods have less chance of squirrels taking over the box.

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SELECTING A HOUSE

Look through any book or catalog and you'll see bird houses of all sizes and shapes, with perches and without, made of materials you might not have thought of: recycled paper, gourds, plastic, rubber, pottery, metal, and concrete.

So what makes a "good" bird house? It's a combination of quality materials and design.

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MATERIALS

It makes no difference whether the wood is slab, rough-cut or finished, as long as the inside has not been treated with stains or preservatives. Fumes from the chemicals could harm the birds.

There's no need to paint cypress and cedar, but pine and plywood houses will last longer with a coat of water based exterior latex paint. White is the color for purple martin houses. Tan, gray, or dull green works best for the other cavity nesting species. The dull, light colors reflect heat and are less conspicuous to predators. Don't paint the inside of the box or the entrance hole.

Regardless of which wood you select, gluing all the joints before you nail them will extend the life of your bird house. Galvanized or brass shank nails, hinges, and screws resist rusting and hold boxes together more tightly as they age.

Resist the temptation to put a metal roof on your bird house. Reflective metal makes sense for martin houses up on a sixteen-foot pole, but when it's tacked onto a roof of a wood chickadee house, the metal is more likely to attract predators.

Natural gourds make very attractive bird houses. They "breathe," and because they sway in the wind are less likely to be taken over by house sparrows and starlings.

Grow your own gourds and you'll have dozens to choose from in the years ahead. If you don't have the space to grow them, a coat of polyurethane or exterior latex (on the outside only) will add years to the one you have.

Properly designed pottery, aluminum (for purple martins only), concrete, and plastic houses will breathe and are durable, but don't drop them.

Be sure to provide ventilation, drainage, and easy access for maintenance and monitoring. Concrete (actually a mix of concrete and sawdust) offers protection other houses cannot: squirrels cannot chew their way in.

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DESIGN

                 Box      Box      Entrance   Entrance   Placement
                 floor    height   height     diameter   height
   Species       inches   inches   inches     inches     feet
   ===============================================================
   American
   Robin*        7x8        8      ---         ---       6-15
   ---------------------------------------------------------------
   Eastern 
   Bluebird      5x5      8-12     6-10       1-1/2      4-6
   ---------------------------------------------------------------
   Western &
   Mountain
   Bluebird      5x5      8-12     6-10       1-9/16     4-6
   ---------------------------------------------------------------
   Chickadees    4x4      8-10     6-8        1-1/8      4-15
   ---------------------------------------------------------------
   Titmice       4x4     10-12     6-10       1-1/4      5-15
   ---------------------------------------------------------------
   Ash-throated
   Flycatcher    6x6      8-12     6-10       1-1/2      5-15
   ---------------------------------------------------------------
   Great
   Crested
   Flycatcher    6x6      8-12     6-10       1-3/4      5-15
   ---------------------------------------------------------------
   Phoebes*      6x6        6      ---         ---       8-12
   ---------------------------------------------------------------
   Brown-headed
   Pygmy and
   Red-breasted
   Nuthatch      4x4      8-10     6-8        1-1/4      5-15
   ---------------------------------------------------------------
   White-
   breasted
   Nuthatch      4x4      8-10     6-8        1-3/8      5-15
   ---------------------------------------------------------------
   Prothonotary
   Warbler       5x5        6      4-5        1-1/8      4-8
   ---------------------------------------------------------------
   Barn
   Swallow*      6x6        6      ---         ---       8-12
   ---------------------------------------------------------------
   Purple
   Martin        6x6        6      1-2        2-1/4      6-20
   ---------------------------------------------------------------
   Tree and
   Violet-Green
   Swallows      5x5      6-8      4-6        1-1/2      5-15
   ---------------------------------------------------------------
   Downy
   Woodpecker    4x4      8-10     6-8        1-1/4      5-15
   ---------------------------------------------------------------
   Hairy
   Woodpecker    6x6     12-15     9-12       1-1/2      8-20
   ---------------------------------------------------------------
   Lewis's
   Woodpecker    7x7     16-18    14-16       2-1/2     12-20
   ---------------------------------------------------------------
   Northern
   Flicker       7x7     16-18    14-16       2-1/2      6-20
   ---------------------------------------------------------------
   Pileated
   Woodpecker    8x8     16-24    12-20        3x4      15-25
   ---------------------------------------------------------------
   Red-Headed
   Woodpecker    6x6     12-15     9-12         2       10-20
   ---------------------------------------------------------------
   Yellow-
   bellied
   Sapsucker     5x5     12-15     9-12       1-1/2     10-20
   ---------------------------------------------------------------
   Bewick's and
   House wrens   4x4      6-8      4-6        1-1/4      5-10
   ---------------------------------------------------------------
   Carolina
   Wren          4x4      6-8      4-6        1-1/2      5-10
   ---------------------------------------------------------------
   Barn Owls    10x18    15-18       4          6       12-18
   ---------------------------------------------------------------
   Screech
   Owls and
   Kestrel       8x8     12-15     9-12         3       10-30
   ---------------------------------------------------------------
   Osprey       48x48 platform
   ---------------------------------------------------------------
   Red-tailed
   Hawk and
   Great
   Horned Owl    24x24 platform
   ---------------------------------------------------------------
   Wood Ducks    10x18   10-24    12-16         4       10-20
   ---------------------------------------------------------------
   *Use nesting shelf, platform with three sides and an open front

Regardless of design, driving rain will get in through the entrance hole. You can assure proper drainage by cutting away the corners of the box floor and by drilling 1/4 inch holes in the box floor. Nest boxes will last longer if the floors are recessed about 1/4 inch.

Entrance Hole

If your box is made of finished wood, add a couple of grooves outside below the hole. Open the front panel and add grooves, cleats, or wire mesh to the inside.

Never put up a bird house with a perch below the entrance hole. Perches offer starlings, house sparrows, and other predators a convenient place to wait for lunch.

Don't be tempted by those beautiful duplexes or houses that have more than one entrance hole. With the exception of purple martins, cavity-nesting birds prefer not to share a house. While these condos look great in your yard, starlings and house sparrows are the only birds inclined to use them.

Accessibility

Part of being a responsible bird house landlord is your willingness to watch out for your tenants. Monitor your bird houses every week and evict unwanted creatures: house sparrows, starlings, rodents, snakes, and insects.

Be careful when you inspect your bird boxes. You may find something other than a bird inside. Don't be surprised to see squirrels, a mouse, a snake, or insects. Look for fleas, flies, mites, larvae, and lice in the bottom of the box.

If you find insects and parasites, your first reaction may be grab the nearest can of insect spray. If you do, use only insecticides known to be safe around birds: 1% rotenone powder or pyrethrin spray. If wasps are a problem, coat the inside top of the box with bar soap.

Here's how to check your nest boxes:

Watch the nest for awhile. If you don't see or hear any birds, go over and tap on the box. If you hear bird sounds, open the top and take a quick peek inside. If everything's okay, close the box. If you see problems (parasites or predators), remove them and close the box.

Here's where a bird house with easy access makes the job simple. Most bird houses can be opened from the top, the side, the front, or the bottom.

Boxes that open from the top and the front provide the easiest access. Opening the box from the top is less likely to disturb nesting birds. It's impossible to open a box from the bottom without the nest falling out. While side- and front-opening boxes are convenient for cleaning and monitoring, they have one drawback: the nestlings may jump out.

If this happens, don't panic. Just pick them up and put them back in the nest. Don't worry that the adults will reject the nestlings if you handle them. That's a myth. Most birds have a terrible sense of smell.

If you clean out your nest boxes after each brood has fledged, several pairs may use the nest throughout the summer. Many cavity nesting birds will not nest again in a box full of old nesting

In the fall, after you've cleaned out your nest boxes for the last time, you can put them in storage or leave them out. Gourds and pottery last longer if you take them in for the winter. You can leave your purple martin houses up, but be sure to plug the entrance holes to discourage starlings and house sparrows.

Leaving your wood and concrete houses out provides shelter for birds, flying squirrels, and other animals during winter.

Each spring be sure to clean out all houses you've left out for the winter.

Limiting Predator Access

The entrance hole is the only thing between a predator and a bird house full of nestlings. By itself, the 3/4" wall isn't wide enough to keep out the arm of a raccoon or house cat.

Add a predator guard a 3/4 inch thick rectangular wood block, to thicken the wall, and you'll discourage sparrows, starlings, and cats.

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BIRD HOUSE PLACEMENT

Not everyone has the habitat for a wood duck, purple martin, or screech owl. On the other hand, just about anyone can attract a robin, titmouse, wren, or chickadee.

Let's assume you've built or bought the "perfect" house. You put it out in your backyard in February. Months pass, and not one bird has landed on it. What's wrong?

It may be that you don't have the right habitat, or it may be where you put the house.

There's lots you can do to modify your land to attract the birds you want to see. It can be as simple as putting out a bird bath or as complicated as planting fruit-bearing shrubs or installing a pond with a waterfall.

But it's much easier just to identify the birds most likely to take to your backyard as it is and put the appropriate nest box in the right place.

Should you hang it from a tree limb, nail it to a fence, or mount it on a pole or a tree trunk?

There's a wide range between how high and low you can place a nest box. Pick a height that's convenient for you. After all, you'll want to watch what goes on and keep the box clean. If you want to watch chickadees from your second floor window or deck, fifteen feet is not unreasonable but it's a lot easier to clean out a box at eye level.

Here are some tips on where to put bird houses:

• houses mounted on metal poles are less vulnerable to predators than houses nailed to tree trunks or hung from tree limbs.
• use no more than four small nest boxes for any one species or one large box per acre.
• put about 100 yards between bluebird boxes and 75 yards between swallow boxes (if you have both species, "pair" the houses with one bluebird box 25 feet from a swallow box. Put the "pair" 100 yards away.)
• don't put bird houses near bird feeders.
• don't put more than one box in a tree, unless the tree is extremely large or the boxes are for different species.
• if you have very hot summers, face the entrance holes of your boxes north or east to avoid overheating the box.

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PROTECTION FROM PREDATORS

Adding a predator guard of sheet metal to the entrance hole is usually enough to keep squirrels out.

Raccoons and Opossums

Snake-proof your house by putting it on a metal pole lathered with vaseline or hot red cayenne pepper.

House Sparrows and Starlings

You can keep bees and wasps from attaching their nests by coating the inside of the roof with bar soap. In areas where gypsy moths abound, avoid placing boxes in oak trees, which are favored by the gypsy moths.

Pyrethrin and rotenone insecticides are recommended for killing fly larvae, bird lice, and miles after birds have finished nesting for the season.

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PROTECTING BIRD HABITAT

You can help preserve wetlands for wildlife by buying Federal Duck Stamps at your local post office. Money from sales of these Stamps is used to buy more wetlands. For more information write: Director, U.S. Fish and Wildlife Service, Department of the Interior, Washington, D.C. 20240.

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SUGGESTED READING

Trees, Shrubs, and Vines for Attracting Birds by Richard DeGraff and Gretchen Wit. University of Massachusetts Press, 1979.

How to Attract Birds by Ortho Books, 1983.

30 Birds That Will Nest in Birdhouses by R.B. Layton, Nature Book Publishing Company, 1977.

The Birder's Handbook: A Field Guide to the Natural History of Noah American Birds by Paul Ehrlich, David Dobkin, and Darryl Wheye. Simon and Schuster, 1988.

The Bluebird: How You Can Help Fight For Its Survival by Lawrence Zeleny, Indiana University Press, 1976.

Planting A Refuge for Wildlife: How to Create A Backyard Habitat for Florida's Birds and Beasts by Cerulean, Botha, and Legare. Florida Game and Freshwater Fish Commission, Tallahassee.

American Wildlife and Plants: A Guide to Wildlife Food Habits by Martin, Zim, and Nelson. Dover Publications, 1961.

A Field Guide to the Nests, Eggs, and Nestings of North American Birds by Colin Harrison. Viking Press, 1984.

Woodworking For Wildlife by Carrol Henderson. Minnesota Department of Natural Resources, St. Paul, 1984

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