Instructions
Listen all the time. Pay attention to the different sounds and calls you hear even if you can't sort through them yet. Familiarize yourself with the variety of sounds. This helps when you start trying to identify specific bird calls.
Listen for tone. Some species such as the American Cardinal make a variety of noises, but the tone of their calls remains the same. Practice makes perfect on this one. The more you listen, the more in tune you become with different tones.
Learn common birds' songs first. They are easier to recognize because you hear them more often. Repetition is the key to learning any new task and this is no exception. In fact, many of these birds willingly oblige you their songs whether night or day.
Go bird watching at sunrise. Birds are more active and a lot noisier at this time of day. If you start when it is still dark, you will hear the different species join the chorus one at a time, making it easier to sort out their voices.
Use classic phrases with the same number of syllables to help you remember the bird calls. Also, make up your own. For example, a white-throated sparrow says "Oh sweet Canada, Canada, Canada." If the bird call sounds more like, "Over here kitty, kitty, kitty" to you, go with it.
Listen to recordings of bird calls. There are free resources online and several quality products available at the book store. Listen while cleaning your house or driving in the car. Take the bird calls in one at a time. Start with three or four birds common in your area.
Visit a local park and take a walk with a naturalist. The best way to sort out the bird calls is to take a trained ear along for the ride. Naturalists should know which bird is making which call. Ask her to help you sort out difficult calls and warn you about imposters.