Getting Started With Bluebirds
Over the years, land has been cleared for housing and industrial developments, shopping malls, highways, and cropland; many old trees have been cut down for firewood. Wooden fence posts that provided nesting cavities have now been replaced with metal posts. With modernization, the supply of natural nesting cavities for bluebirds and other native cavity nesters has been greatly reduced.
Compounding the problem of habitat loss has been the introduction into North America of two imported species - the House Sparrow and the European Starling. Both starlings and sparrows are cavity nesters, and both are very aggressive. House Sparrows are small enough to enter any hole that a bluebird can, and are so aggressive that they will chase away the more timid bluebird. Starlings can be excluded from bluebird houses by using the correct size entrance hole, but will out-compete bluebirds for woodpecker holes and other natural nesting cavities.
During the summer, bluebirds feed mainly on insects. In the winter, bluebirds depend on many kinds of wild berries for their food supply. However, the supply of wild berries has also decreased over the years. The few berries that remain are often stripped quickly by large flocks of starlings.
Even though the bluebird population has greatly decreased, the future can still be promising for them. The most important step we can take to help bring back the bluebird is to provide nesting sites by setting out a bluebird house or starting a bluebird trail. A bluebird trail is a series of bluebird houses placed along a prescribed route. In areas where bluebird houses have been put up in suitable habitat, bluebird populations are increasing. Bluebirding is a great environmental, hands-on project that people of all ages can enjoy. By following the instructions below, chances are good that you will be able to attract and enjoy bluebirds.
THE BLUEBIRD HOUSE
A good bluebird house should be well ventilated, watertight, have drainage holes, be easy to monitor, and easy to clean.
Cedar, redwood and eastern white pine are ideal, although plywood and other types of wood can be used. Houses can be painted or stained if a light color is used.
Treated lumber should not be used because of its toxic content.
A bluebird house should never have a perch. Sparrows and wrens are attracted to perches.
Houses for Eastern Bluebirds should have a round entrance hole of 1 1/2"; Mountain Bluebirds need an entrance hole of 1 9/16"; Western Bluebirds will use a 1 1/2" hole, but a 1 9/16" hole should be used where the Western & Mountain Bluebird ranges overlap.
Oval holes should measure 1 3/8" x 2 1/4" for the Eastern Bluebird.
MOUNTING THE BLUEBIRD HOUSE
Smooth round pipe is probably the best and simplest mounting system to use -- 3/4" electrical conduit works well, but any smooth scrap round pipe will also work.
Coating the pole with grease will also help to keep predators off the bluebird house.
Hardware cloth placed under a bluebird house helps to prevent snake predation.
Unless your trail is in an area where raccoons are not present, avoid mounting bluebird houses on a fence line or on trees. Raccoons are known to walk fence lines and may find your bluebird houses.
SETTING UP A BLUEBIRD TRAIL
Habitat is the key factor to consider when setting up a bluebird trail. Open rural country with scattered trees and low or sparse ground cover is best. Suitable habitat should include perch sites, such as a fence line, wires, or tree branches where bluebirds may perch to search for food. Look for these when you are selecting a location for your bluebird houses. If bluebirds do not like the habitat, they probably will not use your houses.
Pastureland, acreages, parks away from human traffic, and mowed areas such as cemeteries, golf courses are all good locations for a bluebird trail (provided pesticides are not used).
Avoid brushy and heavily wooded areas -- this is the habitat of the House Wren.
Avoid areas where the House Sparrow is abundant (i.e. farmsteads and feedlots).
Avoid areas of heavy pesticide use.
Mount bluebird houses so the entrance hole is approximately five feet above the ground. If possible, face the house away from prevailing winds and facing towards a tree or shrub which is within 100 feet of the house. Trees and shrubs provide a landing spot for the young bluebirds when they first leave the house. This will keep them off the ground, away from predators.
Houses for the Eastern Bluebird should be spaced at least 100 to 150 yards apart; Western and Mountain Bluebirds have a larger nesting territory and houses should be spaced no closer than 300 yards apart.
Bluebird houses can be mounted in pairs in areas where Tree Swallows are abundant. When paired, houses should be mounted 5 to 25 feet apart. This provides nesting sites for both species and helps to prevent competition between them. Different species of birds usually do not mind nesting close to each other.
Bluebirds rarely nest in cities. It is possible, but uncommon, for bluebirds to nest along the outer edges of cities or in small towns. Bluebirds generally prefer rural areas.
MONITORING A BLUEBIRD TRAIL
Do not put up a bluebird house if you do not plan to monitor it. Check your bluebird houses at least once a week during the nesting season, until chicks are close to fledging.
Do not open the house after nestlings are 12 to 14 days old. Doing so could result in the nestlings leaving the house before they are able to fly, greatly reducing their chance of survival.
Always remove House Sparrow nests immediately.
Have your bluebird houses in place by mid-March when the bluebirds return from their winter migration and are looking for nesting sites. However, bluebird houses may also be put up later in the nesting season.
Bluebirds usually nest in late March or early April, depending on weather conditions. In southern states, where bluebirds reside year round, nesting may occur earlier.
Bluebirds usually have two broods per season, but three broods are possible.
Recognize a bluebird nest -- It is a cup-shaped nest that is usually made up of 100% woven grass. Pine needles may be used.
Bluebirds usually lay 4 to 5 light blue eggs, but may lay as many as 6 or 7. A small percentage of their eggs may be white.
The incubation period for bluebird eggs is 12 to 14 days.
Nestlings remain in the nest 18 to 21 days before they fledge.
Remove bluebird nests and those of other birds as soon as the young birds have fledged.
Keep records of the activity on your bluebird trail.