Hacker and writer Joshua Klein is fascinated by crows. After a long amateur study of corvid behavior, he's come up with an elegant machine that may form a new bond between animal and human.

Different bird species have distinct calls that they recognize and pay attention to. Play the compilation video below and see if you can recognize any of the bird sounds; these birds are specific to North America. 


The first six birds have familiar calls, the next six displays birds that are widespread across North America, and the final set has some trickier birds. If you think that you're an expert or know of someone who is, have them play the video blindfolded - you'll be interested to see how they respond!

Penguins may lack teeth, but they have backward facing spines in their throats that grip and guide fish down.

The sword-billed hummingbird’s bill is actually longer than its entire body. As the sole species in the Ensifera genus, this hummingbird is found across South America. The bill can grow up to 14 cm, so these birds have to use their feet to groom themselves and typically rest with their bill pointed upward so they can balance.

Meet the fruit dove. These colourful, frugivorous doves are found in forests and woodlands in Southeast Asia and Oceania. Males and females of many fruit dove species look very different. For example, the female Many-coloured Fruit Dove shares the male’s crimson crown and deep pink undertail feathers, but is otherwise green, whereas the male has a crimson on the upper back and has areas of yellow, olive, cinnamon, and grey.

Birds are very clever animals. They exhibit a wide range of smart behaviors, including good memories, extensive communication, planning for the future, and remembering the past. Some birds can solve problems, and others are capable of adapting to new environments and conditions.

Experts often think of intelligence in terms of creative abilities used to solve problems. Some scientists believe that tool-using birds show such abilities. The woodpecker finch (first from left) of the Galapagos Islands, for example, has learned to use a cactus spine or small twig as a probe to remove carpenter bee larvae from their tunnels. The Egyptian vulture (second from left) uses rocks to break open ostrich eggs. Gulls learn to drop clams and turtles onto roc ...

Some birds, such as woodcreepers and cuckoos, are known to follow army ant raids on forest floors. As the army ant colony travels on the forest floor, they stir up various flying insect species. As the insects flee from the army ants, the birds following the ants catch the fleeing insects. In this way, the army ants and the birds are in a commensalistic relationship because the birds benefit while the army ants are unaffected. ...

Further visual proof suggesting the relationship between birds and dinosaurs!