Range & Season
Most birds look differently during different seasons. During the breeding season, they are dressed in their best colors and their behavior is noticeably different. After breeding, they "molt" either before they leave for their winter habitat or before they return to their breeding grounds.
It's very important to know what birds are around during each season. You can find this information by looking at the range/season maps in a field guide. For our area, you can refer to Range Bayer's List of Lincoln County Birds or use the Oregon Breeding Bird Atlas which is available from Oregon Field Ornithologists, POB 10373, Eugene, OR 97440.
A great example of seasonal changes occurs with the Rufous Hummingbird. These hummingbirds spend the winter in Mexico and Central America. When the time comes, the males leave their winter homes. They follow the Pacific coast feeding on the nectar of early-blooming red-flowering currants, Indian Plums, salmonberry flowers and other native plants. They also find plenty of protein eating small spiders and other insects. The males arrive in Waldport during February. The males stake out territory along the way and some Rufous Hummingbirds head to Alaska and breed there. Within a few weeks, the females and last year's young arrive. The adult males stay in the Waldport area until mid-summer and then head to the mountains and then back to their wintering grounds in Mexico and Central American. The females and young don't leave the Waldport area until late September or early October.
Here on the Oregon coast, if you see a hummingbird in December, chances are it is not a Rufous Hummingbird because they have migrated south. Chances are you are seeing an Anna's Hummingbird because they spend the winter in Waldport. In fact, female Anna's Hummingbirds are collecting nesting material for their nests in January and February.
By knowing which birds migrate into and out of your backyard, you'll have the advantage of knowing when to expect company and when they will be leaving. You can set up special food sources, water or shelter for them during the months they are in your backyard. For example, you can hang cotton in January for the Anna's Hummingbirds to use for their nests.