We've had a rip-roaring start to spring, with some very wintry weather! The evidence of spring did appear one sunny morning between storms, when a Western bluebird perched outside my patio door. I had never seen one so close up before.
The Western bluebird, scientific name Sialia mexicana, is a member of the thrush family. The male has a deep blue head, back and wings with a robin-red breast and crescent on the back of its neck. The female has a dusty-gray back with dull blue wings and tail. Youngsters look like females, with more gray overall and speckled underparts.
Their territory ranges from southern British Columbia, down the West Coast of the United States to Baja and central Mexico (note the "mexicana" in the scientific name), then east to the Rockies and south to west Texas.
Populations are declining in some areas. The Audubon Society has listed the Western bluebird as a candidate for being listed as a threatened and endangered species due to limited range or habitat in Washington and because it is a sensitive (vulnerable) species in Oregon and Utah.
Western bluebirds live in open woodlands near the edges of forests and are frequent winter drifters in piñon-juniper woodlands. In spring, they look for old trees with cavities or woodpecker holes that can provide a place for their nests. A lack of nesting holes limits where they breed.
Once a male finds a suitable hole for a nest, he entices the female with a flashy display that also serves to repel rivals for her affection. Hopefully, the female will produce four or five pale blue eggs sheltered in a grass nest inside the cavity.
Western bluebirds eat mainly insects, particularly grasshoppers, but also caterpillars, beetles, ants, bees and wasps.
They also eat fruit, such as elderberries, mistletoe berries, weed seeds and a few seeds of other species. They do not usually consume grain. Their diet from fall to early spring includes the berries of mistletoe, juniper and coffeeberry. Flock density in winter depends on availability of mistletoe and juniper berries.
Predators of the Western bluebird include hawks and owls. European starlings, house sparrows and some woodpeckers compete for their nests and destroy their eggs and nestlings.
Nest boxes are available. Those placed on trees were more successful than those placed on fence posts. Western bluebirds use large nest boxes with 3-inch-diameter entrance holes, if no other sites are available. Nest boxes may attract Western bluebirds to areas where they would not normally live.
For more information, e-mail skellyj@unce.unr.edu or call me at 887-2252. You can "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu or call your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu.
- JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.
