Crows and Jays: Corvidae
CROWS AND JAYS: CorvidaeBLUE JAY (Cyanocitta cristata): SPECIES ACCOUNTS
WESTERN SCRUB-JAY (Aphelocoma californica): SPECIES ACCOUNTS
GREEN MAGPIE (Cissa chinensis): SPECIES ACCOUNTS
SPOTTED NUTCRACKER (Nucifraga caryocatactes): SPECIES ACCOUNTS
NORTHERN RAVEN (Corvus corax): SPECIES ACCOUNTS
Corvids, members of the Corvidae family, range in length from 7.4 inches (19 centimeters) in Hume's ground jay to the northern raven, which is 22.62 to 26.91 inches (58 to 69 centimeters) long. Hume's ground jays weigh 1.47 to 1.61 ounces (42 to 46 grams). Northern ravens range from 2.02 to 3.43 pounds (.92 to 1.6 kilograms).
The Corvus genus of crows includes the crow, raven, jackdaw, and rook. These birds have shiny black plumage, feathers, and harsh calls. Jays are the colorful members of this family. The Eurasian jay and blue jay have blue and white feathers. Magpies are related to jays and plumage (feather) color is often described in the names of these birds, like the green magpie.
Corvids have strong bills. Most birds have black or dark bills, and feathers or whisker-like bristles cover the nostrils of many birds. Members of this family have large feet with strong toes. Birds use their toes to hold onto prey, the food that they hunt.
Corvids have long tails and rounded wings. Wing length varies with the amount of flying a bird does. Long wings are found on birds that migrate, travel long distances from one place to another.
Corvids belong to the Passeriformes, song bird or perching bird, order. While other birds in this order sing sweetly, the corvids' loud, harsh calls are described as screeching or croaking sounds.
Corvids are located throughout most of the world. They are found on all continents except Antarctica.
Members of this large family live in habitats ranging from treeless tundras where land is flat to mountain forests. Birds live in deciduous forests, where trees shed their leaves, and coniferous forests, with cone-bearing evergreen trees. Corvids range in deserts, grassland steppes where there are few trees, and on the edge of rainforests, where heavy rain produces much growth. In addition, corvids live in cities and small villages.
Corvids mainly eat seeds and nuts. However, they are omnivores, eat animals and plants. These birds are scavengers and take food from places like garbage dumps. Another corvid habit is hoarding food. Birds hide food, often burying it. They stockpile food for times like winter when there is a shortage of seeds and nuts.
BEHAVIOR AND REPRODUCTION
Corvids are family-oriented. Many species travel in a flock, a group of birds. Birds in this group are monogamous (muh-NAH-guh-mus), with a single male mating with a single female. The female corvid lays from two to seven eggs. Females incubate the clutch of eggs, sitting on them to keep them warm.
Older offspring act as cooperative breeders, helping the parents protect and rear young. The male and the older offspring feed the female. They also protect the female from predators like cats, hawks, and people. A mob, usually a group of crows or jays, will fly after hawks and owls. The corvids yell loudly, scolding the birds as they chase them away.
Corvid eggs do not all hatch at the same time. The young birds stay in the nest from five weeks to three months.
CLEVER CROWS FIND FOOD
A prime example of crows' intelligence is how birds solve the problem of getting food. Hooded crows in Finland know that lines left in the water by fishermen lead to food. The birds use their bills and feet to pull up the line and get fish. And in New Zealand, New Caledonian crows make tools out of leaves. Bird use the hooked tools to get hard-to-reach insects.
CROWS, JAYS, AND PEOPLE
People have mixed feelings about corvids. Birds can imitate human words and have been kept as pets. However, people have also killed corvids to prevent damage to crops and cattle.
Corvid names have long been used to describe negative traits in humans. For example, to crow means to brag, and to rook is to cheat. The little-used verb raven means hunt for prey, and ravenous means extremely hungry. A jay is a foolish person, and a magpie is someone who chatters or collects many things.
According to the World Conservation Union (IUCN), the Hawaiian crow is Critically Endangered, facing an extremely high risk of extinction; four species are Endangered, facing a very high risk of extinction; eight species are Vulnerable, facing a high risk of extinction; and eleven species are Near Threatened, in danger of becoming threatened with extinction. The primary cause is the destruction of habitat as trees are cut down.
Physical characteristics: Blue jays are colorful members of the crow family. They have a crest of blue feathers that tops their head. Their rounded wings and fan-shaped tails are dark blue with black and white markings. Blue jays have pale gray faces and bodies. There's a "necklace" of black feathers around the throat. The bird has a long black bill, long legs and black feet.
Adult blue jays range in length from 9.36 to 11.7 inches (24 to 30 centimeters). Birds weigh from 2.27 to 3.8 ounces (65 to 109 grams). The wingspan is 16 inches (40.54 centimeters).
Physical characteristics: Western scrub-jays look somewhat like blue jays. Both species have dark blue heads, wings, and tails. The scrub-jays do not have feathered crests on their heads. Scrub-jays have white chests, and white coloring on the face that resembles an eyebrow. The throat is white with a blue necklace. There is a blue band on the chest, and the lower body coloring is white, tan, and gray.
The length of western scrub-jays ranges from 10.53 to 12.09 inches (27 to 31 centimeters). They weigh about 3 ounces (85 grams).
Geographic range: Western scrub-jays live in the western United States and northwestern Mexico.
Habitat: Western scrub-jays live in desert areas.
Diet: Western scrub-jays are omnivores. They eat acorns, pine seeds, invertebrates, animals without backbones, like insects, reptiles, eggs and nestlings, mammals, and amphibians, animals able to live on land and in the water.
Behavior and reproduction: Western scrub-jays are solitary breeders. The male and female are not helped by other birds. The female lays two to six eggs from March through May. Females incubate the eggs, which hatch after sixteen to nineteen days. Birds fledge, grow feathers, in approximately eighteen days.
Western scrub-jays and people: Seeds hidden by western scrub-jays grow into trees.
Conservation status: Western scrub-jays are not in danger of extinction. ∎
Physical characteristics: Green magpies have bright green heads and reddish brown wings. Their bodies are a lighter green, and their long, tapered tails have white tips. Black coloring on the face resembles a mask. Flesh around the eyes is red, and their bills, legs, and feet are also bright red. Green magpies range in length from 14.43 to 15.21 inches (37 to 39 centimeters). They weigh from 4.55 to 4.65 ounces (120 to 124 grams).
Geographic range: Green magpies live on the continent of Asia and are found in India, China, Malaysia, Borneo, and Sumatra.
Habitat: Green magpies live in forests and build nests in vines and in bamboo, which are woody, evergreen trees. Evergreens are coniferous trees that do not undergo seasonal changes.
Diet: Green magpies hunt for food on the ground and in trees. The magpies eat insects, small reptiles, young birds, eggs, amphibians, berries, and fruit. Magpies also eat the flesh of recently killed animals.
Behavior and reproduction: Green magpies are solitary breeders. The male and female birds do not receive help, such as protection, from their older offspring. The magpie nest resembles a platform. The female magpie lays three to seven eggs during the months of January through April. Green magpies remain hidden during this time, and it is not known how long it takes for eggs to hatch. Within their habitat, groups of green magpies fly around with other groups of birds.
Green magpies and people: Green magpies, which are also known as cissas, are captured and sold as cage birds.
Conservation status: Green magpies are not in danger of extinction. ∎
Physical characteristics: Spotted nutcrackers are named for their appearance and the way they use their large bills to take the shells off of nuts. There are white spots and streaks in their feathers. The spotted nutcracker's brown body plumage is the color of chocolate. The lower part of the body is white. The wing and tail feathers are a shiny black. There are white tips at the ends of the wings and feathers. The spotted nutcracker's bill, legs, and feet are black.
The length of nutcrackers ranges from 12.48 to 13.26 inches (32 to 34 centimeters). Birds weigh from 4.3 to 7 ounces (124 to 200 grams).
Geographic range: Spotted nutcrackers live in Europe and are found in nations including Switzerland, England, Netherlands, and Scandinavian countries. The birds also range in Japan, China, and other Asian countries.
Habitat: Spotted nutcrackers live in coniferous forests, where trees such as pines do not shed their leaves.
Diet: Spotted nutcrackers eat conifer seeds, or nuts, of trees in the pine and spruce families. Larger birds eat the hard-shelled hazel nuts. Spotted nutcrackers get the edible meat inside the shell by hitting the shell with their bill.
Spotted nutcrackers have thick bills that they use to open nuts. They place the nut between their feet and then begin pecking on the shell. Nutcrackers use their beaks to hit the nut until the shell cracks.
Like other corvids, nutcrackers store food. They bury nuts and seeds to eat at a later time. If no seeds or nuts can be found, nutcrackers eat insects and berries.
Behavior and reproduction: Spotted nutcrackers are solitary breeders. The female lays two to four eggs during March through May. The female incubates the eggs that hatch in eighteen days. Both parents feed the chicks. The young birds fledge after about three weeks. The nestlings remain with their parents throughout the summer or longer.
Spotted nutcrackers and people: Seeds hidden by spotted nutcrackers sometimes sprout into saplings that grow into trees. The spotted nutcracker's habit of hiding food caused the growth of new Swiss pine trees in areas of the European Alps where people had cut down all the trees.
Conservation status: Spotted nutcrackers are not in danger of extinction. ∎
Physical characteristics: Northern ravens have shiny black plumage, black bills, and black legs and feet. These birds have long bills. There are long, pointed feathers around the neck. The length of northern ravens ranges from 22.62 to 26.91 inches (58 to 69 centimeters). Birds weigh from 2.02 to 3.43 pounds (92 to 156 grams).
Geographic range: Northern ravens are found throughout the Northern Hemisphere. In North America they range from Alaska to Greenland, south through Canada, and into the United States and Mexico. In the United States they are typically found west of the Rocky Mountains and along the east coast from Canada to Georgia. Birds also range throughout Europe.
Habitat: Northern ravens live in many different habitats, including the treeless tundra. They choose locations away from people.
Diet: Northern ravens eat carrion, the decaying bodies of dead animals. They use their strong bills to rip into dead animals or kill live prey. Ravens also eat plants and berries.
Behavior and reproduction: Northern ravens have long-term mating partners. The female raven lays from three to seven eggs in the spring. Eggs hatch in eighteen to twenty-one days. Birds grow feathers five to six weeks later.
Northern ravens and people: People killed northern ravens because they wrongly blamed ravens for the death of cattle. The raven is a symbol of death and the bird's ability to say words is the subject of Edgar Allen Poe's poem, "The Raven."
Conservation status: Northern ravens are not threatened. ∎
FOR MORE INFORMATION
Stuart, Chris and Tilde. Birds of Africa From Seabirds to Seed Eaters. Cambridge, MA: The MIT Press, 1999.
Youth, Howard. "The Revered, Reviled Crow Clan." ZooGoer 30, no. 3 (2001). Online at http://nationalzoo.si.edu/publications/zoogoer/2001/3/reviledcrowclan.cfm (accessed on July 20, 2004).