can be very instrumental in increasing the population of your
insect-eating Bluebirds, by monitoring the activities in and around
Bird Houses in your neighborhood.
This is best accomplished with houses which have a panel that opens
easily for inspection of the interior. Keep records of what and when,
you witness conditions, in and around the bird houses.
Since most Bluebird Houses are mounted at eye level, it is easy to see
into the nest. By February 1, you should have the houses cleaned out
and ready for occupants. A weekly inspection will alert you to any
nest-building activities. Carry Binoculars for bird identification.
Your houses should have a 1-1/2" diameter hole to exclude larger birds,
especially Starlings which this writer has personally seen evict a much
larger Flicker, from a Flicker Nest Box placed high in a tree.
It's helpful to be able to recognize nests, in order to know who built
them. Bluebirds tend to use soft grasses throughout. Tree Swallows use
grasses, but usually line the nest bowl with feathers.
English Sparrows make a bulky nest and have feathers included rather
haphazardly. House Wrens use twigs frequently dotted with wads of
Spider Web and an occasional feather. The builder can often be
identified by nesting materials on the ground beneath the house.
If you want to accommodate Bluebirds, you have the option of removing
the nests of other birds or adding more Bird Houses. Number them for
If you are just starting a Trail, remember that Bluebirds are
"territorial" and chase other Bluebirds from their vicinity to protect
their food supply. They also defend their nests to varying degrees. I
have a pair that will gang up on any nearby Starling or English
Sparrow. Other birds which pose no threat, are allowed to rest on the
The houses should be 200 or more feet apart. This distance is
influenced by obstructions such as trees and buildings between the nest
boxes. It also depends on the aggressiveness of the individual birds.
When you open a house, do it carefully; there could be a snake which
remembers it found food here last year, or a Wasp Nest brimming with
defenders. Either must be unceremoniously removed from the house.
Approach houses from the rear or side, and tap on the rear to alert any
birds that may be inside. Early in the nesting season they may fly from
the house, but later when there are Eggs or Nestlings, they may sit
tight if you are slow and gentle with your monitoring. You may even be
able to take a photo of the mamma crouched down in her nest.
When you find a nest and you're not sure who built it, surveillance
with Binoculars from a nearby vantage point will help confirm their
identification. Then you can decide to remove it or monitor it.
It should be noted here that Wrens tend to build partial nests in many
houses, whether for practice or to dissuade other birds from building
in their territory. Unless a house is filled to the top with twigs, you
may want to eliminate these practice nests.
Once you find a nest with Eggs, you'll know you're in business; you're
about to become a proud Grandparent. But watch closely, because within
3 weeks of hatching, they'll be gone. Isn't that amazing?
Now the record-keeping starts: Make note of the date and time and
weather conditions, including average daily temperature. How many Eggs,
their color and patterns, as "3 - spreckled white" or whatever. Be
aware that parents will dive-bomb you with beaks snapping.
If one Egg looks different from the rest, you may have a predatory
Egg. Remove them or suffer lost Bluebird Nestlings. Keeping the
entrances at 1-1/2" should prevent the entrance of Cowbirds, but you
may want to monitor nests in shrubs and trees for this predator.
You can describe the nest as "Twigs", Grasses only", or whatever.
Always pull weeds from underneath houses to remove predator cover.
Snakes and Chipmunks are less likely to vandalize in the open.
Note the date when you first see Pin Feathers. And the date their eyes
open. Also note any that appear to be scrawny or different from the
rest. If you want to take photos, it's best to remove the whole nest.
At this time you can check the floor for insect infestation or dampness.
If the nest is especially soiled, and also soiling the Nestling's
it may be best to remove them along with the nest, into a cardboard
box. Put 3" of compressed clean, dry grass clippings in the house, and
carefully replace the Nestlings. Do this quickly to minimize parental
Note when the Nestlings fly. This may be over a 2 or 3-day period. Some
kids just hate to leave the cozy nest, but if the parents sit nearby
and beckon with a yummy Pizza and a color TV or Computer, sooner or
later hunger sets in and nature takes its course.
Then it's time to remove the nest and scrub the house out with 50/50
Chlorine and water. Put a stick inside to open the door while it dries.
If you're lucky, the parents may be starting all over again in several
weeks, after they teach the Fledglings how to fend for themselves.
Three hatchings a year are not uncommon, so keep your notepad handy.
You may welcome Tree Swallows and Wrens into your houses. They can live
together peacefully if you supply adequate housing. They do not compete
for insects. Bluebirds feed on the ground, Wrens search through the
foliage, and Tree Swallows catch insects in the air.
But take every action necessary to discourage English Sparrows! They
are the bane of Bluebird Trails. They will destroy eggs and Nestlings
and build a nest on top of the existing one. Traps are sold to minimize
the toll of this very determined and destructive predator.