| The Western Bluebirds in the Lower Willamette Valley
are not migratory. Many remain in their nesting territories through
out the winter and may be seen inspecting boxes as early as February.
They begin nest building activity between late March and mid-April.
The female does all of the nest building and can complete the task in 3
days; however, she may take 2 to 3 weeks. Usually the nest, which
may be 3 to 5 inches deep, is constructed of fine dry grass. Other
times the female may use rootlets or other available vegetation.
Rarely will you find feathers in a bluebird nest.
Egg laying usually begins in mid-April for the first clutch. A second clutch is usually started a week to 10 days after the first brood fledges. On rare occasions, a third clutch will be attempted. In this case, egg laying may take place as late as mid-July. Four to seven blue eggs are laid, usually at one day intervals. On rare occasions, the eggs may be white rather than blue. Under normal circumstances incubation begins after the last egg is laid, and eggs hatch in 13 to 14 days. Only the female incubates the eggs and broods the featherless nestlings. The male defends the territory and feeds the female and the nestlings. Nestlings are banded when they are 7 to 13 days old. Adults are also trapped and banded using a cage-like trap baited with mealworms. The nestlings remain in the nest for 19 to 22 days. Once they fledge, they will not go back into the nest box. Both the male and the female feed the nestlings spiders, flies, caterpillars, crickets and other high-protein insects. The parents continue to feed the young for several weeks after they leave the nest box. |