Hummingbirds are a fascinating group of birds that includes over 300 species, making them the world's second largest family of birds (the largest family of birds is the flycatcher family). The hummingbird family includes the world's smallest species of bird, the Cuban Bee Hummingbird (Mellisuga helenae), which measures a mere 5-6 cm in length.

Feathers are unique to birds. They are a defining characteristic of the group, meaning simply that if an animal has feathers, then it is a bird. Feathers serve many functions in birds but most notable is the critical role feathers play in enabling birds to fly. Unlike feathers, flight is not a characteristic restricted to birds--bats fly with great agility and insects fluttered through the air several million years before birds joined them. But feathers have enabled birds to refine flight to an art form matched by no other organism alive today.

Identifying a bird can be challenging. Birds are active, energetic animals and you need a quick eye to spot as many details as possible in a short span of time. The obstacles are many--the light may be dim, you could have the sun in your eyes, or the bird may dive into a bush. So to stand the best chance of landing a name for a bird, you'll want to know what to look for--what matters most and how to spend your precious viewing time.

You can test your animal identification skills in this series of little quizzes aimed at helping you to become familiar with a variety of animal species.