Bluebirds often nest in bird houses. You can buy bluebird houses already
built from gardening and bird feeding stores, or you can build your
own. Plans for a bluebird box that is designed to attract bluebirds
and to keep predators out from the Minnesota Department of Natural
Houses should be in place each year by mid-March to
attract birds returning from migration. But bluebirds nest two or three
times a season, so often accept boxes put up later for second nestings.
Bluebirds will only nest in boxes that are in the appropriate habitat.
Open rural country with scattered trees and low or sparse ground cover
is best. Pastureland, acreages, some parks and mowed areas such as cemeteries
or golf courses are all good locations for a bluebird trail. if no pesticides
are used on them. Here are some additional hints about the habitat they
Try to provide a fence line, wires, or tree branches
where bluebirds may perch to search for food.
Avoid brushy and heavily wooded areas -- this is
the habitat of the House Wren, which may puncture bluebird
Avoid farmsteads and feedlots where House Sparrows
may be abundant. They take over bluebird boxes, often killing
Avoid areas of heavy pesticide use.
Boxes for the Eastern Bluebird should be spaced
at least 100 to 150 yards apart; Western and Mountain Bluebirds
have a larger nesting territory and boxes should be spaced
no closer than 300 yards apart.
Mount nesting boxes so the entrance hole is about five feet above the ground.
If possible, face the box where a tree or shrub is in view no more than
100 feet from the box; this will provide a safe landing spot for the
young bluebirds when they first leave the box, keeping them off the ground,
away from predators.
Nesting bluebirds face many dangers. We can protect them from:
House Sparrows: House sparrows
aggressively take over bluebird nest boxes, often killing the bluebirds.
It's important to check your houses at least once a week to throw
out House Sparrow nests as they start. House Sparrow nests are
tall, made of coarse grasses, often with pieces of scrap paper,
cellophane, or other garbage. The nest forms a canopy with a tunnel-like
entrance. Their eggs are cream-colored with brown markings. In
comparison, bluebirds make a deep cup-shaped nest out of fine grasses
or pine needles. Bluebird eggs are blue.
- Tree Swallows: You are not legally allowed to disturb
Tree Swallow nests. If Tree Swallows are nesting in your bluebird boxes,
set your boxes in pairs. 5-25 feet apart. Swallows and bluebirds are
territorial, and will normally keep members of their own species out
of the second box. But bluebirds and swallows seldom mind nesting close
to each other. So providing two boxes gives both species nesting sites.
Tree Swallow nests are made of grasses, and usually have white feathers
in their top layer. Tree Swallow eggs are white.
European Starlings: Make sure
the entrance hole in your bluebird box is no bigger than 1 1/2
inches to keep starlings out.
Blowflies: Blowflies are extremely
dangerous parasites on nestling birds which parent bluebirds
simply do not notice or know how to guard against. To protect baby
you must actually check them by monitoring the nest. Here is
what the North American Bluebird Society says about monitoring nests: "Nest
monitoring should only be done during calm, mild, and dry weather
conditions to reduce the chance of chilling the chicks or eggs.
Open the nest box being careful not to allow the eggs to fall out
or chicks to jump out. Songbirds have a very poor sense of smell
and will not abandon the nest due to your handling the nest, eggs,
or chicks. If chicks are in the nest, look under the nest for signs
of blowfly larvae. The chicks themselves should be examined for
small scars, particularly under the wings which indicates blowfly
parasitism. Sometimes you may observe the larvae attached to the
chick. These are easily removed by hand. Complete the monitoring
as quickly as possible to minimize disturbance. When handling the
chicks or removing them from the nest they should be placed in
something that will protect them from the sun or wind while preventing
their escape. Avoid disposing used nest material near the nest
site or predators may be attracted to the site. Always be certain
to close the box door securely before leaving." The Bluebird
Society says, "If you identify larvae in the nest, you
should replace all the nest material with dried lawn clippings
in a shape
similar to that of the original nest. This will increase the
chance that the chicks will survive. Many bluebird enthusiasts
all nests holding chicks periodically even before the blowfly
larvae are visible."
Once babies are 12 days old, don't approach the nest anymore of the babies
might fledge too early, which is dangerous.
For more information about bluebirds, see the