Why Monitor?

It is important that bluebird nest boxes be actively monitored (checked) weekly or at least every 2 weeks, during the nesting season.  A box that is not monitored may be more harmful than helpful to bluebirds. Monitoring nest boxes will alert you to problems the birds my be having with parasites, predators or nest box repair requirements.

MBT would like you to monitor and report all species using your nest boxes, not just bluebirds.  Other cavity nesters such as tree swallows, house wrens, and chickadees are all native and beneficial birds.

After any nesting effort has ended, either due to nest failure or successful fledging of the young, the nest should be removed from the box.  If a bluebird nest was successful, re-nesting in the same box will be encouraged if the first nest is removed.

If you do not clean out your nest boxes the previous fall, be sure they are cleaned out before the bluebirds start arriving from early February to mid-March.

What to Monitor?

You should record the date, and the number of eggs or young that you have observed.  Bluebirds lay one egg each day until the entire clutch is complete.  Incubation will then begin and will last approximately 13-14 days.  After hatching the chicks will remain in the nest for 17-18 days.

Design a recording chart for yourself and make columns for:

1. Box Number
2. Date
3. If a nest was present and its stage of construction
4. Eggs are present and how many
5. If there were chicks and how many
6. How many fledged
7. Type of Bird

How to Monitor

Open the nest box being careful not to allow the eggs to fall out or chicks to jump out.  Songbirds have very poor sense of smell and will not abandon the nest due to your handling the nest, eggs, or chicks.  Complete the monitoring as quickly as possible to minimize disturbance.

Identifying Eggs

Bluebird: The 1-4 in. tall nest is built with fine grasses or pine needles with a fairly deep nest cup. Eggs (4-6) are powder blue or occasionally white.

Tree swallow: Their nest is also made of grasses but they may use somewhat coarser fibers than a bluebird. The nest generally has a flatter cup than the bluebird's and is usually lined with feathers or occasionally scraps of paper. Eggs (5-7) are white and smaller than those of a bluebird.

House wren: Wrens fill a nest box with sticks and line the deep nest cup with fine plant fibers or feathers. "Dummy nests" without the nest cup are often built in all other cavities within the male wren's territory to reduce competition for resources. The eggs (6-8) are tan, speckled with brown and quite small.

Black-capped chickadee: Chickadees build a nest of moss and plant down with the nest cup lined with hair. They lay 5-8 white eggs covered with brown speckles. Eggs are often covered with moss when the female leaves the box.

House sparrow: House sparrows build a tall nest of coarse grasses, often with pieces of scrap paper, cellophane, or other garbage. The nest forms a canopy with a tunnel-like entrance to the 5-7 cream-colored eggs with brown markings.