Birds are grouped by physical characteristics. It is fairly easy to distinguish a duck from a songbird by just looking at body shape and size, as well as the beak and feet shapes. However, most of the birds coming to feeders are songbirds, (perching birds) so they have similar characteristics.
These physical characteristics will help identify birds: size, body shape, colors, markings, beak shape, feet and wing shape in flight.
Birds have a variety of calls. Good listeners can learn to tell the difference between “chickadee” and “cheerily – cheerio – cheeriup” calls of the Black-capped Chickadee and the American Robin.
Bird behaviors can also help identify birds, such as flight pattern, feeding behavior, display habitat type and social group.