 Housing
Montana Natives One Pair at a Time
Anyone who lives in western Montana will
tell you that wintertime lasts a long time. For months, the
land is locked in winter’s icy grip and I always wait
eagerly for the beginning of spring. For me, there is one
event I look forward to, one event that shouts: “spring is
here!” (And it isn’t a groundhog coming out of his hole!)
Around the end of February snow starts to disappear and I
constantly watch outside for the first sign of spring.
Usually I’m left waiting until at least the first week of
March. Then it happens: riding the back of one of the last
winter storms of the year, the harbingers of spring return
to my family’s ranch. Last spring, when it was all over, I
had four western bluebirds sitting in a row on the back of
one of my lawn chairs. They made it back early—snow still
covered the ground. Even so, the bluebirds returned to their
summer nesting range and bluebird season began once again
for my husband and me. Bluebirds have always been part of
our ranch and the surrounding area and we want them to
continue nesting here for generations to come.
The first task of the season is to check the status of all
of our nest boxes and do a little spring-cleaning. When we
first started eight years ago, we only had a couple of boxes
on our family ranch. Today, we monitor more than sixty nest
boxes in various locations, called a “bluebird trail.”
During our first outing of the season we make sure the boxes
are still clean from the fall-cleaning and we evict unwanted
guests such as mice, chipmunks, and squirrels who may have
moved in for the winter. We also make necessary repairs,
such as fixing roofs, replacing the bottoms of boxes,
remaking entry holes and replacing old boxes as needed. A
common problem we face with our nest boxes is keeping the
entry hole the correct size. The pesky woodpeckers and
flickers that live in our area frequently enlarge the entry
holes. The size of the entry hole on a nest box is crucial,
bluebirds require a 1 9/16” entry hole since this size
eliminates starlings from being able to enter and,
therefore, compete for the box. After we accomplish all our
preliminary chores, we wait until mid-April to begin
regularly monitoring our boxes.
 In
early spring, sometimes starting in the second week of
March, male bluebirds finish scouting out and claiming
territories that will attract their mate and provide the
best shelters for raising families. Bluebirds are secondary
cavity nesters, which means they rely on cavities carved out
by other birds, like woodpeckers, or naturally occurring
cavities such as sandstone cliffs or clay banks. One of the
reasons my husband and I started a bluebird trail on our
ranch was to provide nest boxes to replace the holey fence
posts the bluebirds had probably been using over the years.
As one version of a “secondary cavity,” the birds easily
accept the nest boxes we’ve built for them, which they will
use to start building their nests..
Nest building usually begins in late April throughout
western Montana. The male may bring his mate bits of nesting
material, but it is the female who builds the nest.
Depending on available material, she may select dry grasses,
dry bark, pine needles, twigs, straw, and hair from horses
and deer. The nest cup is then lined with finer materials.
Some pairs will complete a nest in as little as a day or
two, and others will take as long as a week. The habitat
surrounding the nesting site is important also. Bluebirds
are primarily insect eaters, so they prefer open spaces with
plenty of perches from which they can keep a constant look
out for meals. The hayfields, pastureland, short grass areas
and open ponderosa pine flats on our ranch provide the ideal
habitat for bluebirds. Additionally, these areas are also
away from a major competitor for the boxes: the English
house sparrow.
By late spring the bluebirds are in the process of laying
and incubating their eggs, with the weather playing a
crucial role in determining when the process is completed.
Spring storms can delay the egg laying process as far as
into the middle of May. At this stage, my husband and I
monitor the boxes regularly, checking them each week. To
monitor a box, one must approach quietly from its side
(never walking in front of the hole), cover the entry hole
with a hand or plug it with a cloth and slowly and carefully
open the lid to view its contents. A quick peek into the box
ensures that the nest is intact and the number of
eggs/nestlings is counted. Then, I secure the lid, remove
the plug and leave quickly and quietly. The parents are
usually not far away and I use binoculars to get a better
view of them in order to note which species is using the
box. On our ranch, and in the rest of western Montana, there
are two species of bluebirds: the mountain bluebird and the
western bluebird. It is quite easy to tell the two species
apart since the mountain bluebird is almost entirely pale
blue-grey in color, and the western bluebird has a bright
blue head with an orange-brown breast.
Over the coming weeks we will be back often to check the
status of the nest boxes. We record the number of nestlings
that have successfully hatched and, later on, the number of
young birds or fledglings who have successfully left their
nests. To provide even more in depth information on our
bluebird trail, I recently learned how to band bluebirds.
The small aluminum band is placed on one of the birds’ legs
and has a personal identification number, which can be used
to track the bird through online resources. The numbers
provide information about who banded the bird, and when and
where they were banded. When the nestlings are mature
enough, but haven’t left the nest, I return to band them.
The information collected from our monitoring is sent to
Mountain Bluebird Trails, Inc. and is used to help monitor
the status of bluebird conservation in Montana. Fledgling
Reports are available on the website:
www.mountainbluebirdtrails.com
When we’re out monitoring, we often find other native
Montana species using the nest boxes. These include swallows
(by far the most common), nuthatches, chickadees and the
occasional wren. Although our first love is for bluebirds,
we enjoy watching the others raise their families in our
boxes as well. The same, however, cannot be said for
starlings and european sparrows. Both of these species were
introduced in the 1850s and compete aggressively for nesting
cavities. They will destroy bluebird eggs, kill nestlings
and will even kill the mother bluebird as she incubates her
eggs. These species are a significant problem for all native
birds, and are one of the reasons native songbird
populations have declined. We do not tolerate them on our
trail.
The weeks quickly fly by and before long the first set or
clutch of hatchlings have been fledged. Then the process
begins again. Bluebirds are capable of having two clutches
of five to six eggs during one season if the conditions are
favorable, so monitoring our trail and keeping the nest
boxes clean and serviceable is crucial. Then, late fall
quickly comes, the bluebirds migrate south, and the season
is over for another year. 2006 was a successful year: a
total of one hundred and thirty fledglings left our nest
boxes. We are looking forward to the spring of 2007…..and
maybe adding a few more boxes!
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