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.

Photo © Chas53 / iStockphoto.

In today's animal identification challenge, we have a little grey and white bird with a splash of orange on its flanks. This little bird is about 6.5 inches in length with a 9.75 inch wingspan. It is common in mature deciduous forests in the US, east of the Mississippi River. Its song is whistled "peter peter peter peter" and its call is a series of thin nasal notes, "ti ti ti sii sii zhree zhree zhree". The adult has a black forehead, pale cream feathers around the eye, and a blue-gray crest and upper body. It has a splash of rusty orange feathers on its flanks just beneath its wing. This species does not migrate, choosing instead to brave the cold throughout the winter months throughout its range.

Your task is to identify which of the following three birds this species is: nuthatch, tufted titmouse, or chickadee.

After you have cast your vote in this Animal ID Challenge, be sure to check your answer here.

For paper wasps, it pays to have a unique face. That's what Michael Sheehan and Elizabeth Tibbetts of University of Michigan concluded in a recent paper published in the journal Evolution. Their research reveals that paper wasps (Polistes fuscatus) that have distinct facial markings become embroiled fewer aggressive conflicts than those that had facial markings that made them less easily distinguished from fellow wasps.

"It's good to be different, to wear a nametag advertising your identity," said Michael Sheehan.

In previous research, Elizabeth Tibbetts showed that paper wasps are able to recognize eqch others based on their distinct facial markings. Now, this latest research reveals just how a unique face can help an individual wasps by enabling it to avoid unnecessary confrontations with other wasps.

Tibbets and Sheehan set up experiments in which they modified the facial patterns of wasps and evaluated the aggressive behavior among individuals in the group. Each group had three wasps whose faces they modified to look similar as well as a fourth wasp whose facial markings were distinct from the other three. Tibbets and Sheehan observed that the wasps that were recognizable—those with the unique facial marking—experienced less aggression than those with less distinct markings. They reasoned that if an individual is reconginzed, repeated aggression is not ncessary as previous social interactions have already settled the question of social status.

Photo © Michael Sheehan / University of Michigan.

Photo © Mark A. Klingler / Carnegie Museum of Natural History.

A team of paleontologists have discovered a fossil of a 123-million-year-old mammal that lived in what is now the Lianoning Province of northeastern China. The mammal, Maotherium asiaticus, was so well preserved that it has provided scientists with new insights into the evolution of the mammalian middle ear.

"What is most surprising, and thus scientifically interesting, is this animal's ear. Mammals have highly sensitive hearing, far better than the hearing capacity of all other vertebrates, and hearing is fundamental to the mammalian way of life. The mammalian ear evolution is important for understanding the origins of key mammalian adaptations." ~ Dr. Zhe-Xi Luo, from Carnegie Museum of Natural History.

Mammals possess more acute hearing than other vertebrates, an adaptation that enabled early mammals to better evade predators in the dinosaur-dominated environment in which they first evolved. Mammalian hearing depends on three bones, the hammer (malleus), the anvil (incus), and the stirrup (stapes) as well as an eardrum (tympanic membrane). These structures were once part of the jaw bone in mammalian ancestors. In present day mammals, the bones are separate from the jaw. But in Maotherium asiaticus, there is still a connection between the middle ear bones and the jaw.

NPR has a fantastic collection of 15 images from a new book by photographer Michael Forsberg, Great Plains: America's Lingering Wild.

This week, PBS is showing a six-part documentary by Ken Burns, The National Parks: America's Best Idea. You can find out more about the series here and here. If you missed any of the episodes that have already aired (like I did) you can view them online here.

This collection of images shows what divers photographed while participating the whale shark photo monitoring project.