About Bluebird Living Arrangements
In the wild bluebirds raise their young in nests. The eastern bluebird nests in April to June in the north and mid country and April to May in the south. They normally build their nests in hollow trees, woodpecker holes or holes in fence posts. The nesting material is dried grasses, stems, dried pine needles and feathers. There are four to six eggs per clutch and they will have two to three broods per year. The incubation period is 12 days. This is another good reason not to take away dead trees unless they are a hazard or are unsightly.
All bluebirds will make use of a birdhouse but they are a bit picky and have certain design requirements. The opening should be pretty close to 1 1/2 inches and best if it is six inches from the floor of the house. Bluebirds do not care if the opening is six inches from the floor, but this distance protects them from predators. Starlings are serious predators of bluebirds and they will attack and eat both the eggs and the young. The survival rate of the young may be based on whether or not starlings can reach the nest, so try for six inches. Bluebirds prefer the house is not painted especially on the inside. Bluebird houses are available commercially having all the correct dimensions and design considerations included. We particularly like the versions with a viewing glass so children can see the babies without disturbing them too much.
Building Your Own House
You can make your own bluebird house using the dimensions in this drawing. The best bluebirds houses allow for easy access for cleaning and so you can more easily kick out the squatters like the sparrows and swallows.
The box should be from 3 1/2 X 3 1/2 to 5 1/2 X 5 1/2 inches by 8 inches high. Bluebirds do not need a perch to sit on before they enter the house. To prevent blowfly parasites on young bluebirds, bend a 3/8th inch mesh, hardware cloth so that it sits one inch from the floor and covers the entire floor space. The blowfly larvae will fall through the wire and be unable to climb back into the nest. We do this because the blowfly larvae can harm and even kill baby bluebirds.
Locating A Bluebird House
The house can be placed on the side of a tree, fence post or a post placed just for the house. The bluebird requires open spaces and that is why most bluebird houses are on a post placed in an open field. The box should be placed four to eight feet from the ground. Some bluebird enthusiasts believe it is best to set the house three to five feet off the ground because this height discourages sparrows which will attack the nest and young. This is also the height needed to monitor the nest box and clean out the nesting material daily if the inhabitants are not bluebirds. The nesting hole should face north, east or northeast to prevent sunlight from shining into the hole and overheating the box interior. The east is the best. The houses should be placed at least 100 yards from each other because of the territorial needs of the specie.
Evicting The Squatters
Because sparrows and swallows will often chose to set up house keeping in a bluebird house, you have to be vigilant and tough about keeping them out. Until you see the bluebirds moving in, you need to check the house every day during nesting season to see if any squatters are moving in. Both sparrows and swallows are perfectly capable of finding nesting sites in other spots so don’t be wishy-washy, pull out the nesting material of those birds as soon as you see them moving in. Sometimes you have to clean out the house four or five days in a row before they get the idea and move on.
If you feel bad about this eviction process, install some more bird houses around your property for the swallows and sparrows since they are great insect eaters as well.
Cleaning The Bluebird House
After the bluebirds have raised their family we recommend that you clean out the nesting box after each brood has flown away, about three weeks from hatch time. The cleaning of the nest box has nothing to do with the bluebird’s sanitation requirements. It has to do with the building of a new nest on top of the old nest. The new nest will shorten the distance the nest is located from the opening. The new nest will no longer be at the same distance as the old nest, giving the starlings a clearer advantage when they try to attack the eggs and young.
While generally, when you clean out any birdhouse of old nesting material you take away everything. Bluebirds are the exception. When the blue bird box is cleaned, leave some of the old nesting material lying on the in the bottom. It may contain the pupae of tiny parasitic wasps that kill blowfly larvae, which sometimes pray on nesting blue birds.