Birds need additional energy to make it through the cold nights. They also need to replenish the lost energy when wake up in the morning. I always recommend that you have your bird feeders full the last couple of daylight hours and at daybreak. This is to help birds endure the long winter nights and fill those empty bellies in the morning. I put out Black Oil Sunflower seed and suet. Roosting boxes are a big help as small birds will gather on the perches and “huddle up” to stay warm over night.