Georgia depression population Sialia mexicana)
This member of the thrush family is 15 to 18 cm long. Males are deep purple-blue on top and a paler blue underneath; females are a more muted shade of blue, with a grey throat and belly and have a white eye-ring. The western bluebird was once widespread across southern B.C., including Vancouver Island. No nesting pairs have been documented on Vancouver Island or the Gulf Islands since 1995, and the species is now considered to be extirpated from the Georgia Depression area (southeastern Vancouver Island, Vancouver and Olympic Peninsula). Following a successful re-introduction of bluebirds to Washington’s San Juan Is., several conservation groups in the Cowichan Valley collaborated to re-introduce the western bluebird
(PDF) to a Garry oak preserve
in that region in 2012. Several breeding pairs were released, with more to be released in following years. Nest boxes have been installed throughout the preserve, as well as other areas of southern Vancouver Is. and the Gulf Islands.
Western Bluebirds eat invertebrates such as grasshoppers, crickets, caterpillars, moths, beetles, ants, termites, wasps and bees, spiders and flies. They are “secondary cavity nesters”, using tree cavities previously excavated by woodpeckers, especially in open woodlands such as Garry oak meadows
, at low elevations. The loss of these ecosystems, and removal of old trees with cavities, are the most likely causes of their disappearance from this region. Only 3% of historic Garry oak ecosystems remain in a fairly natural state in BC, and even these are threatened with invasive species
and encroachment of other native species due to fire suppression. Introduced house sparrows and European starlings may also compete for nest sites with bluebirds.
Additional Information ©Image courtesy of Yathin (flickr.com)