A strong Arctic old front blew through recently with frigid temperatures, strong winds and ice. The bluebird box was covered with ice and cold, but I think the birds roosted in it. Rarely do they spend the night in the box. Oklahoma bluebirds don’t migrate, so they must adapt their preferred diet of insects to include berries and seeds. The lucky ones on the reddirt heal get some additional rations of plump mealworms in cold weather.
Don’t forget to feed the birds in icy weather. Ice is especially hard on birds because their food sources are encased in the ice. Song birds primarily keep warm by burning calories and some additional food in cold weather helps them stay warm.