Whoever came up with the clever idea of a child returning home
from the dentist’s office and shouting, "Look Ma, no
cavities!" made history. This exclamation is very fitting
for humans but not for birds. Around 85 species of birds in
North America depend upon cavities, natural or man-made, for
nesting, and one of those of our region is the eastern bluebird.
Sadly, the number of natural cavities is steadily decreasing.
It was Dr. Lawrence Zeleny, influential bluebird promoter and
author of what many consider to be the finest book ever written
about bluebirds, "The Bluebird: How You Can Help Its Fight
for Survival", who influenced thousands of people to build
bluebird nest boxes and also establish and monitor bluebird
trails.
Dr. Zeleny’s study of the eastern bluebird revealed that their
drastic decline already had begun in the 1920’s and continued
into the late 1970’s. Upwards of 90% of their total population
was lost to various causes including especially the extremely
severe winters of 1976-77 and 1977-78 when so many either starved
or froze to death.
An active group, the "North American Bluebird
Society" (NABS) was begun during the bluebirds’ hard times
to help them. NABS continues its great work to this day. Their
address: NABS, Box 6295, Silver Spring, MD 20906-0295 will get
you some information.
No to be overlooked is our own state’s excellent group of
dedicated bluebirders: "Bluebird Restoration Association of
Wisconsin, Inc. BRAW, 4303 Timber lane, Rhinelander, WI 54501.
Charlotte and I have learned a lot from attending annual meetings
of these dedicated people, and much of the following information
has been gleaned from these worthwhile get-togethers.
The Kentucky-style bluebird nest box I have written about in
the past, and which has proved to be so successful on our land,
surely is not the best house in the eyes of many other people who
build and care for bluebirds. I happen to like it because it’s
so durable, easy to build and also to erect. A lot of people
swear by the Peterson bluebird house, designed by Dick Peterson
of Brooklyn Center, MN. It’s quite heavy and difficult to build
because of its unusual angles – but it works very well. Dick, by
the way, has co-authored an excellent book with Steve Grooms
called, "Bluebirds." Its colored photos and
illustrations are awesome.
Bluebirds have been known to arrive in northeastern Wisconsin
as early as mid-March in some mild springs, which is why it’s
wise to have your nest boxes ready plenty early. The good news
is that two-thirds of the bluebirds nest after June 1. Given
normal weather, it takes the female around 14 days to lay the
eggs, 14 days for them to hatch, and at least 14-15 days before
the young leave the nest. Should the weather during nesting be
wet and cold, seriously affecting the numbers of available
insects for the birds, the young may remain in the nest for as
long as 22-23 days.
What surprised me is the fact that, upon taking their very
first flight, their solo flight, some of the baby bluebirds are
known to fly as far as 100-125 feet away from the bird house and
often to a fairly high tree. They have a built-in tendency to
remain there for safety and where the adults will feed them. All
the while they are flying from one branch to another as they
strengthen their flight muscles and learn the intricacies of
flying. Gradually they will work downward in the tree until
finally they learn to hunt for their own food near or at ground
level.
One of Charlotte’s most memorable experiences last summer
happened while she was working in our garden. Suddenly she heard
much bird "conversation" to her back. She turned and
saw the four baby bluebirds perched on top of the west end of the
garden fence with papa, learning to hunt for food. All the
while, mama bluebird was incubating her second clutch of four
eggs less than 40 yards away, using the very same, very clean
nest in which the first brood was raised.
The feature about the Kentucky house that I especially like is
the "U"-shaped entrance directly below the roof. This
virtually eliminates house sparrows that, when nesting, build a
mounded-over nest which is impossible to do with this type of
entrance. Predators, including fox snakes, feral cats and
raccoons, can be very damaging to nesting bluebirds. Using
half-inch electrical conduit pipe on which to mount the nest box
virtually eliminates these predators for the simple reason that
they ca n’t climb the thin pipe. A liberal coating of
carnauba-type car wax smeared onto the pipe adds further
insurance against the climbers.
The relatively large "U"-shaped entrance does away
with the need for ventilation holes or slots. Furthermore,
research has learned that black flies will not enter a dark box.
Vent holes light up the interior of a box. Black flies can
accumulate on the baby bluebirds and easily kill them, a fairly
common problem when the houses are near wetlands where black
flies are more abundant.
Unpainted cedar or pine lumber, used in the construction of
the boxes, will weather to a beautiful gray in a year or two. If
you are going to paint your nest boxes, paint only the outer
surfaces. A good mixture is made from flat white oil-based paint
and a little linseed oil. By the way, never use treated lumber
for birdhouses due to the harmful chemicals that very likely will
affect the inhabitants.
Placing your boxes near small dead trees is prefect because
bluebirds love these natural perches, especially for hunting
insects on the ground below. It’s ideal to face your houses away
from the prevailing wind – north or east is the best. If the box
is erected along a road, face it away from the road.
Do all you can to help these magnificent birds and surely
"You will find the bluebird of happiness!"
Even though bluebirds will not begin nesting this early,
it is a good idea to have your nest boxes cleaned and set out by mid-March.
Bluebirds will use the boxes to roost during cold spring nights.
This column appeared in the Door County Advocate
on 03/06/2004.
© Copyright 2004 Roy Lukes. All rights reserved.
