Corvidae

Corvidae is a family of very smart birds. It includes crows, ravens, rooks, magpies, jackdaws, jays, treepies, choughs, and nutcrackers. There are 135 known types of corvids. The genus Corvus has 47 of these types. The raven is the largest kind of passerine bird.

Corvids are known for their amazing intelligence. They have shown self-awareness in tests, like the Eurasian magpie. They can even make tools, a skill once thought to belong only to humans and a few animals. Their brain-to-body size ratio is similar to that of great apes and whales, and only a little smaller than humans.

These birds are medium to large. They have strong feet and beaks. Corvids live all over the world except for the southern tip of South America and the polar ice caps. Most corvid types are found in tropical South and Central America and southern Asia, with fewer in Africa and Australasia. Some raven types on islands far from land are in danger of extinction.

Systematics, taxonomy, and evolution

The name Corvidae was introduced in 1820 by an English scientist. Corvids include crows, ravens, magpies, and jays. They started in Australasia and spread around the world.

Scientists use DNA to study their family tree. This shows that jays and magpies are from different groups. Some birds once thought to be corvids, like the crested jayshrike, are now in different families. Fossils of corvids are about 17 million years old and have been found in Europe and other places.

Morphology

Corvids are big birds with strong legs and bodies. Most have special feathers on their noses, except for the pinyon jay. Their feathers are often black or blue, but some tropical birds are very colorful. Both males and females usually look alike.

These birds have strong beaks and large wings. The dwarf jay is the smallest, weighing about 41 grams. The common raven and the thick-billed raven are among the largest, often weighing more than 1,400 grams. You can tell them apart by their size, shape, and where they live.

Ecology

Corvids, like crows and magpies, live in many parts of the world. They usually stay in one place. But when there is less food, they may travel to find more.

Crows are good at sharing spaces where they breed. This lets more crows live in the same area than birds like ravens.

Some people worried that crows and magpies might hurt smaller birds by taking their eggs. But studies show this is not a big problem. For example, American crows did not cause fewer marbled murrelets. And Eurasian magpies did not affect many songbird populations. Other things, like habitat destruction, matter more.

Behaviour

Some corvids, like jackdaws, live in groups with jobs to do. They help each other by sharing food and looking after baby birds together. Young corvids love to play games, like balancing sticks, which teaches them skills they will need to survive.

These birds pick their partners through fun contests. Some, like blue jays, can be fierce when guarding their nests and may chase away animals that come too close.

Food and feeding

Corvids eat many kinds of food, such as insects, small animals, fruits, and seeds. Some, like crows, live close to people and eat food like bread and dog food. They also help by eating pests that can damage crops, like cutworms and grasshoppers.

Reproduction

Corvids usually stay together in strong pairs and work together to build big nests. They lay between 3 and 10 eggs, and both mom and dad help take care of the baby birds. Some corvids, like rooks and jackdaws, even live and nest in large groups.

Intelligence

A Canada jay pair feeding their chicks.

Corvids are very clever birds, with big brains for their size. They can solve hard problems, use tools, and remember where they hid food for many months. For example, New Caledonian crows make hooks from twigs to catch insects. Their cleverness helps them survive and live in groups.

Disease

Corvids, like crows and ravens, can carry the West Nile virus. They get this virus from mosquitoes, especially those of the Culex species. When these birds die from the virus, it can be one of the first signs that the West Nile virus has arrived in a new area. This happened in 1999 when crows began dying in New York.

Relationship with humans

The Hawaiian crow is extinct in the wild as a result of habitat loss and other factors.

Some corvids, like ravens, have been kept as pets, but they are not as easy to care for as parrots and do not do well in cages. In the United States, it is illegal to own any migratory bird, including corvids, without a special permit under the Migratory Bird Act.

Humans have shared spaces with corvids such as crows and ravens for a long time. These birds appear in many stories and traditions around the world. For example, some Native Americans believed ravens helped create the earth, while Celtic peoples linked them to war and the gods. In Germanic peoples myths, Odin had two ravens who brought him news from everywhere. Corvids are also popular characters in books and poems, showing their important place in human culture.

Species

Rufous treepie, Dendrocitta vagabunda

The Corvidae family includes crows, ravens, magpies, jays, and nutcrackers, among other birds. There are 135 species in this family. The genus Corvus alone has 47 species, making up over a third of all corvids.