 |
The Eastern Bluebird
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 species 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 boxes 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 box
or starting a Bluebird trail. A Bluebird trail is a series of Bluebird boxes
placed along a prescribed route. In areas where nesting boxes 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 Nestbox
A good
Bluebird box should be well ventilated, watertight, have drainage holes, be
easy to monitor, and easy to clean. Cedar and redwood are ideal, although .
plywood and other types of wood can be used. Boxes can be painted or stained
if a light color is used.
- Treated lumber
should not be used because of its toxic content.
- A Bluebird box
should never have a perch. Sparrows and wrens are attracted to perches.
- Boxes 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 Nestbox
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
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 nesting boxes. If Bluebirds do
not like the habitat, they probably will not use your boxes
- 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 nesting boxes
so the entrance hole is approximately five feet above the ground. If
possible, face the box away from prevailing winds and facing towards a
tree or shrub which is within 100 feet of the box. Trees and shrubs
provide a landing spot for the young Bluebirds when they first leave the
box. This will keep them off the ground, away from predators.
- 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.
- Boxes can be
mounted in pairs in areas where Tree Swallows are abundant. When paired,
boxes 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 box if you do not plan to monitor it. Check your Bluebird boxes
at least once a week during the nesting season, until chicks are close to
fledging.
- Do not open the box
after nestlings are 12 to 14 days old. Doing so could result in the
nestlings leaving the box before they are able to fly, greatly reducing
their chance of survival.
- Always remove House
Sparrow nests immediately.
- Have your Bluebird
boxes in place by mid-March when the Bluebirds return from their winter
migration and are looking for nesting sites. However, boxes 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 16 to 21 days before they fledge.
- Fledglings depend
on their parents to feed them for at least two or three weeks after
fledging.
- 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.
Don't be discouraged if your nesting boxes are not
used the first year. If Bluebirds are not common in your area, it may take
them a few seasons to find your new box. Bluebirds generally return to the
same area each year. Bluebird trails have been an extremely effective method
of reestablishing the Bluebird populations across North America.
Getting Started
text taken from JennaBird.com
For your convenience, we have available the Nest Summary Worksheet from Cornell Lab of Ornithology
Form for each nest monitored and each new nest attempt on
this page.
Cornell Lab of Ornithology's "The Birdhouse Network" (TBN) is
where you can click on the "instructions" tab to get more worksheets.
Cornell Lab of Ornithology home page
Check out our links page for access to more Bluebird information.
Home
Maryland Bluebird Society - Updated 7/13/2007 12:10 AM EST.
|
