Western Bluebirds use grasslands and oak savannahs for foraging. They rely on cavities in oaks for nesting and scattered trees or shrubs as hunting perches.
Limiting factors
This species is threatened by habitat loss and degradation. Invasive, non-native plants and lack of fire have adversely affected habitat in many areas. Bluebirds face competition for cavities from non-native birds. Heavy predation by house cats, raccoons, and rodents is a further stressor. Western Bluebirds are sensitive to disease and parasites.
Data gaps
Evaluate the effects of contaminants (insecticides) on insectivorous bird species. Identify locations of natural cavity-nesting pairs and factors affecting their breeding success.
Conservation actions
Maintain or restore grassland and oak savannah habitat. Maintain oaks >22 inches diameter at breast height. Retain snags and live trees with large, dead branches to improve availability of nest cavities. Maintain nest box programs for cavity habitat in the short-term; design and place nest boxes to minimize use by starlings. Brush/slash piles created as a result of management activities may provide limited, temporary habitat in young conifer forests. Maintain >20% combination of short, herbaceous vegetation and/or bare ground in breeding areas. Monitor and manage for understory vegetation diversity to support an abundance of invertebrate prey.
