The weather this winter in northern areas has been brutally cold and unpredictable and it's just getting started. Some of you have written to us expressing surprise and concern that you are seeing bluebirds in northern areas in winter. Here's some tips to help them survive. You can make a difference.
1. Bluebirds can roost together in bird houses to keep warm. Insulate your bird houses by closing off all cracks, drainage holes, etc., with some sort of insulating material so less drafts and cold get into the bird house. Just leave the entrance hole open. Face bird houses away from prevailing winter winds.
2. Bluebirds mainly eat fruit and berries in winter. Plant your property with an abundance of crabapples and native, berry-producing shrubs such as viburnums and hollies (like winterberry holly). Place these berry plantings in sunny, protected areas, blocked from winter winds. The bluebirds will have a warm place to eat and use less precious energy.
3. Some bluebirds will come to food such as, hulled sunflower, suet, dried mealworms, and some of the many "bluebird meal mixtures" or nuggets. Generally most bluebirds do not do this but they may learn to do so, especially if you get them used to these foods in spring and summer when bluebirds are nesting near you. You can certainly try putting out these foods in winter and if bluebirds come to them, keep feeding all through the winter. Your best bet is to also have lots of berries planted in your yard.
4. Bluebirds like water (may help with processing the berries) and will visit bird baths and heated bird baths. In general, when it is very severely cold, some people think it is a risk for birds to bathe. Holding off on the water, or placing sticks over the bird bath to only allow birds to drink, not bathe, may be a good idea in this situation. Many birds will eat snow in winter to get water.
Most bluebirds move out of the northernmost areas of their range in winter. Even ones that may linger eventually move on, once their berry sources are depleted or ice-covered. For bluebirds, and many birds, there is a trade-off of staying more north in order to be first to claim prime breeding territories, yet risking survival due to bad weather. Some of these tips may help them survive and you feel you're helping them. Bluebirds are truly beloved. Make sure and have nest boxes cleaned out and ready when bluebirds return in spring.
For more complete information see Stokes Bluebird Book.