BLUEBIRD NEST BOX USAGE & MONITORING – by HCBS
Use a ventilated leak-proof box with a doorway small enough to exclude starlings. Place boxes no closer together than 100 yards. Place doorway about five feet above the ground facing away from strong sun and wind.
Free-standing pole-mounts deter cats and raccoons. Thick posts can hold heavy boxes. Lightweight boxes can be supported by narrow metal pipes slipped over 4-foot lengths of half-inch-diameter rebar. The rebar should be sunk about one foot into the ground. Obstacles to climbing and slithering predators are pole grease, tippable discs, and wire-mesh-ended stovepipe.
Choose a site a bit apart from any woods and amid a half-acre of meadow or yard with other perches for bluebirds to sight-hunt for their insect diet. Scattered trees, fences, or support wires make good perches for the hunt.
Monitoring the box during nest-building will allow verification of bluebird occupancy. Bluebirds make very tidy, swirled, cup-shaped nests about three inches high by using only non-coarse grasses or else pine needles.
Wrens fill many boxes with twigs, but frequently do not occupy any boxes. Nest boxes are thereby wasted since bluebirds do not ever clear them out. Such false nests should be removed to allow bluebirds to claim the boxes.
Chickadees make very low nests of moss with fur, feathers, or downy plant material. Titmice use bark and dry leaves with grass, moss, fur, or string in a cup-like shape. Swallows arrange grass with feathers into a hollow ball. These birds can exist peacefully with a second box nearby for bluebirds.
We may choose to leave the nest materials placed by those friendly birds, but we MUST remove all messy nests of vicious English house sparrows. Such nests are balls of grass, weeds, and trash with fur, feathers, or string. House sparrows will attack and destroy bluebird adults, chicks, and eggs!
Monitoring the bluebird nest box is essential for fighting attacks by English house sparrows. A spring-door trap may be used in a nest box so long as the trap is checked daily to prevent captive dehydration. Traps hold birds unharmed for relocation or for later disposal if they threaten the bluebirds.
Extended entry tubes and clear fishing-line webs may also deter enemies.
English house sparrows should be targeted in ANY way that is safe on your property. They are a cruel, non-native, and non-legally-protected species.
Monitoring during nest-building affords the opportunity to retain exactly a bluebird nest in the box. Monitoring during egg-laying and early brooding provides a check for blowfly or mite infestation and for rain-soaking of the nest. Larvae should be removed from chicks and nest. If needed, a new nest may be made from lawn clippings to replace any wet or infested one. Be sure to place chicks in a safe container during the nest exchange.
It is wise to carefully open a bluebird nest box to monitor the progress of nest-building, egg-laying, incubation, and very early nestling growth, BUT the nest box should NOT be opened once the chicks are twelve days old. Risky premature fledging might occur. Nestlings must not be encouraged to leave the nest until they are strong enough for a first flight to the trees.
Once the male bluebird has a site and a partner, the couple builds a nest in about a week (2 to 10 days). The female’s egg-laying begins within a week after the nest is done. One egg appears daily for up to a week (3 to 7 eggs). Bluebird eggs are smooth, oval, and either pale blue or faintly bluish white.
After all eggs are laid, the incubation starts (under female’s brood patch). Eggs hatch after about two weeks (12 to 15 days) of brooding. Mom and Dad feed their nestlings in the nest for under three weeks (15 to 20 days).
On the day of fledging (first flight), all chicks leave the nest, one-by-one. This act of bravery takes the previously box-bound youngsters out of the nest forever. They remain nearby for a few weeks to learn to catch insects. Juveniles sometimes stay in the vicinity to assist the parents’ next brood.
The nest box should be emptied after fledging and cleaned to be ready for a possible second brood. Since nests have an enemy-attracting scent, the old material should not be left nearby. Check again for mites and blowflies. Vary your path to the box so that no scent or trail can guide predators.
Berries, currants, and mealworms (but not seeds) are correct winter food to provide, along with unfrozen water nearby. Bluebirds may stay year-round, using the nest box in extreme cold and then again during the birth season.
Boxes for Eastern bluebirds have a slot entry or a hole that is a 1-1/2-inch circle or a 1-3/8 by 1-1/4 oval. Circle diameter for mountain bluebirds must be 1-9/16 inch. Circular hole for Western bluebirds can be either diameter.
The Bluebird Book by Donald and Lillian Stokes is an excellent reference. The North American Bluebird Society (NABS) can be contacted by mail at PO Box 244, Wilmot OH 44689. The website is www.nabluebirdsociety.org.
This flyer is provided by the Hendricks County Bluebird Society, PO Box 7, Danville IN 46122. The HCBS builds and distributes bluebird nesting boxes and sends newsletters all without charge to bluebird enthusiasts. Optional membership is easily affordable. Call Mary Huber at 317-745-3317 for info or to volunteer for box-building or staffing a booth at the garden show.