Nice to see them in your yard! Yes, Western Bluebirds are year-round residents in Corvallis, and they occur in pairs and small flocks in the winter. Sometimes it seems like numbers are a bit higher in winter than they are during the breeding season. I don't know if they're just more conspicuous now, or if we're seeing some additional wintering birds from east of the Cascades and northern populations.
Some people get bluebirds to visit their feeders by providing foods such as dried mealworms, suet, sunflower seed chips or finely chopped roasted peanuts. Bluebirds will check out nest boxes in the winter, since they may use them as cold-weather roosting sites, and they also keep track of potential nesting sites for spring.
There has been a lot of effort over the past decades to provide bluebird nest boxes throughout the Willamette Valley, and that's had a huge positive impact on their population.
Lisa Millbank