Eastern Bluebirds:

How To Build And Place Nesting Boxes The early American settlers called it the “blue In the yard and around the garden, bluebirds con- robin” because of the rust colored breast and blue sume grasshoppers, flying insects, beetles, and cater- back and tail; today we call it the Eastern bluebird. pillars. They also eat berries and fruits found near Observing this beautiful bird can bring much enjoy- their nest, especially during the winter when insects ment. It is easily attracted to homes and surrounding are scarce. open areas when nesting boxes are correctly con- structed and properly placed. Youth organizations Decline and school classes can construct and maintain During the last 50 years bluebird numbers have bluebird boxes for educational and money-making decreased 90% in the Eastern United States. In fact, projects. the bluebird was ranked second on the National Audubon Society’s 1980 “Blue List” which includes Life History species that could become threatened or endangered The bluebird, like the robin, prefers open areas in the near future. such as roadsides, cutover woodlands, old orchards, There are four reasons for the decline: (1) The parks, and yards in cities and towns. In these areas, widespread use of insecticides decreases food sup- the bluebird tries to find a hollow tree (cavity tree) in plies. (2) Severe winters increase winter mortality. which to construct a loosely woven nest of grasses. (3) Changing agricultural practices create well- These cavities are often hard to find because non- trimmed orchards with no cavity trees for nest sites. native species such as the house sparrow and starling (4) Competition for remaining nest sites by exotic also use cavities for nesting. These exotic species are species such as starlings and house sparrows also very aggressive and often take cavities bluebirds decreases nest site availability. could use. Fortunately, the bluebird will also use man-made cavities, such as boxes, for nesting. The How You Can Help Bluebirds boxes can be constructed to prevent larger birds, such as starlings, from using them. Finding suitable nest sites is perhaps the most Normally bluebirds produce 2 to 3 broods per year severe problem the bluebird faces today. Allowing in North Carolina. The female begins the first nest in trees to mature and develop natural cavities takes too mid-April. She lays one egg per day for 4 to 6 days. long. A much quicker solution is to provide man- The female then incubates the light blue eggs for made wooden nest boxes. These boxes take little time about 12 days. Soon after hatching, the young to build, erect, and maintain. When boxes are placed bluebirds begin sprouting feathers. At this time, in good areas, bluebird populations increase rapidly. bluebirds have a gray back and spotted white breast Providing nest boxes can be a very rewarding with only a hint of blue on their wings and tail. hobby for individuals, clubs, and classes. Not only are Young birds remain in the nest for about 15 days af- bluebirds pleasing to observe, but the activities of ter hatching. box maintenance and checking are “hands-on” The male is in charge of the young bluebirds when educational experiences in avian biology. Clubs and they leave the nest. He feeds them and teaches them other organizations can also generate successful how to find food to feed themselves. He continues money-making projects through bluebird nest box this training phase for several days after they leave construction and sales. the nest. While the male is busy with the fledglings, the female is busy remodeling the old nest or building a new one for a second brood. Figure 1. Plans for bluebird nesting box. ‘7 55” ; 9” 10” 1/4” {I —___——__—- f11/21! ‘v 0 O o — a FLOOR SIDE SIDE BACK 0 TOP O FRONT In 0 O O |‘-*I 8” 1V2” 5 3/4” 10” 9” I 1 3” HOLES FOR WIRE TOP MOUNTING HOLE TO KEEP BOX FOR SCREW FROM SWINGING Directions for Constructing Nest Boxes When constructing bluebird nest boxes, keep two points in mind. First, build boxes the correct size, and second, make boxes easy to clean. DOWN To HOLD TOP Dimensions. If boxes are built to the correct /r—STR|P dimensions they will be somewhat species selective. That is, they will allow bluebirds and bluebird-size birds to enter and nest but will not allow larger birds, O such as starlings, to enter and nest. o u l Use the following dimensions as a guide. Except l for the entrance hole size, these dimensions can vary somewhat. 0 Floor—5% inches x 5% inches Back—5% inches x 13 inches Front—9 inches x 4% inches Sides—5% inches x 9 inches in front and 10 in- ches in back (2 needed for each box) Top—53A inches x 8 inches L%% Entrance hole—11/2-inch round hole 6 inches above the floor (If hole is larger a starling can squeeze in.) Figure 2. Completed bluebird nest box. Construction. Perhaps the simplest and most ef- attach the boxes only through the hole at the top of ficient type of bluebird box to build is the one il- the back piece so that the boxes can be inverted for lustrated below in Figure 1. easy cleaning. Nail or screw the boxes to wood or metal posts. A piece of wire going around the bottom of the box and the mounting structure will keep the 0 Use a single 55-inch long 1 x 6-inch board (These box from swinging too much. boards are usually finished to a %-inch thickness When mounting nest boxes, make it difficult for and 5%inch width). Pine, cedar, cypress, or even predators to get into them. Less predation occurs exterior plywood are all good for box construc- with metal posts because predators such as house tion. cats, raccoon, or snakes have trouble climbing on 0 Cut pieces as shown in Figure 1. smooth metal. Coating the metal posts with grease 0 Cut off about 1/1 inch on each corner of the floor during the nesting season can reduce predation even to allow for drainage. further. Placing a conical or flat sheet metal baffle, 0 Drill 1[4-inch holes, as indicated, to allow for ven- like the ones in Figure 3, just below the box on tilation. wooden posts can also reduce predation. If predation 0 Use 1%-inch galvanized siding or aluminum nails does occur and eggs or young are destroyed, the to fasten the wooden parts together. parents will usually renest in another box nearby. 0 Nail a 1/2-inch x l/2-inch x 5%-inch wooden strip on Nailing a piece of “no-pest” strip 1A-inch x 1-inch to the back board above the top. This small piece the inside of the top each year will help keep wasps holds the top down on the back edge. You can use and mites out of the box. a hinge instead. (Figure 2) 0 Screw the front of the top down using a rust— proof wood screw or lag bolt. For convenience, a Location small latch can be used. 0 DO NOT provide a perch. Bluebirds need no Put nest boxes up by the end of February in areas perch, and perches attract house sparrows to the around open fields, pastures, golf courses, box. cemeteries, gardens, and large lawns which provide excellent bluebird habitat. These areas usually Mounting provide plenty of insects to eat. Avoid areas where in- secticides are used heavily for two reasons: (1) In- Mount nest boxes on fence posts, private utility sects, a favorite bluebird food, are reduced and the poles, tree trunks, or metal posts. It is important to birds have trouble finding enough food to eat. (2) The insects left are usually covered with insecticide. Further Reading Bluebirds may be poisoned when they eat these in- sects. Books: Place. boxes 4 to 6 feet above the ground and 50 to A Field Guide to Birds East of the Rockies. Roger 100 yards apart. Try to select places where trees, Tory Peterson. Houghton Mifflin Co. shrubs, utility wires, or fences are within 25 to 100 American Wildlife and Plants. A. C. Martin et al. feet of the boxes. Bluebirds use these structures for Dover Publ., New York. 1961. perches when feeding. These perches are also helpful Birds of North America. Zim et al. Golden Press. to young birds during their first flights. 1967. If boxes are located near woods and brush piles, Song and Garden Birds ofNorth America. National other species of birds such as chickadees, titmice, Geographic Society. 1964. nuthatches, and wrens will use the bluebird boxes. Songbirds in Your Garden. John K. Terres. Crowell These species, like the bluebird, are welcome addi- Publ. Co. 1968. tions to the area and should not be discouraged from 0.... using boxes. These birds are also helpful in controll- .u.... Pamphlets: ing insect populations. It may be possible to get a Birdwatching with Roger Tory Peterson. National bluebird to nest in the same area by placing another Wildlife Federation. Washington, DC. box about 10 to 20 feet from the One the other bird is Gardening with Wildlife. National Wildlife Federa- usmg. tion. Washington, DC. CONICAL FLAT Invite Wildlife to Your Backyard. National Wildlife Checking Boxes Federation. Washington, DC. Checking bluebird boxes regularly provides infor- Recycle for the Birds. National Wildlife Federation. mation on bluebird productivity. It is not necessary Figure 3. Plans for sheet metal predator guard. Washington, DC. to check boxes. Bluebirds will nest and produce young even if the boxes are not checked regularly. Societies: However, it is fun to see the boxes you constructed North American Bluebird Society, Box 6295, Silver and mounted being used! Bluebird Food Spring, Md 20906. The Society publishes a quar- Starting in early March, check boxes once a week Although the bluebird’s diet is made up mostly of terly journal Sialis, has boxes for sale, and will and continue to do so until July. To check the box un- insects, they do eat berries and fruits. You can im- provide further information on bluebird manage- screw or unlatch the top and look in. Look for prove your yards and gardens as bluebird habitat by ment and programs. evidence of nest building, eggs, or any other signs of planting some of the shrubs and trees listed below. bird activity. Be sure, to record when nest building Both bluebirds and other songbirds will benefit from begins, when and how many eggs are present, when plantings. and how many birds hatch. these Tap the box before opening it so the female can —Autumn olive leave; she will return after a little while. DO NOT —Bayberry or wax myrtle check boxes during the following two periods: During —Blackberry the first 3 days of egg laying, do not disturb the —Blueberry female in the morning hours. This is when she ac- —Elderberry tually lays the eggs. Just remember that when you —Greenbriar see nest construction almost completed, start check- —Hackberry ing the box in the late afternoon. During the last 3 —Honeysuckle days before the young birds leave the box (when they —Mulberry Prepared by‘ are about 10 days old), do not disturb them at any —Serviceberry (Shadbrush) Harry Lee Stribling, Graduate Student time of the day. A disturbance at this time can cause —Viburnum Gary J. San Julian, Extension Wildlife Specialist the young to leave the box prematurely. If young ——Wild grape Department of Zoology leave the box too early, they may starve or be killed —Cedar by a predator. —Cherry Published by During the summer after young birds leave, clean —Dogwood, flowering THE NORTH CAROLINA AGRICULTURAL EXTENSION SERVICE out old nest material so renesting can occur. After —Holly North Carolina State University at Raleigh. North Carolina Agricultural and the last brood leaves late in the summer, leave —Lespedeza Technical State University at Greensboro, and the U. S. Department of Agri- nesting material in the box over the winter. This old —Multiflora rose culture. Cooperating. State University Station, Raleigh, N. 0., Chester D. —Oaks: Laurel, blackjack, water, Black, Director. Distributed in furtherance of the Acts of Congress of May 8 material provides better insulation for birds taking and June 30, 1914. The North CarolinaAgricultural Extension Serviceoffers its refuge in the boxes on cold winter nights. In willow, and live programs to all eligible persons regardless of race, color. or national origin, February, the following year, clean and repair boxes —Pine and is an equal opportunity employer. for the next year’s nesting season. —Sumac 6/82/5M AG-287