Birds are most vulnerable during the winter when they have fewer natural food sources and their usual drinking areas may be frozen over. You can help your local birds by continuing to feed them daily throughout the winter (even if you're not spending much time in your yard watching them). High-fat, nutrient-dense foods such as suet balls and peanuts are ideal. Providing a water source is also very helpful; a bird bath is preferable, but even a dish of water on the ground can be helpful. Just make sure the water does not freeze over in the winter.