The strategy seems to be working: 67 percent of the faux nests are currently in use, making life a lot easier for Chubu employees. Made with non-conductive resin, the nests are placed on company towers high above the power lines, where the birds are unlikely to cause any trouble. To fight back, Chubu started installing artificial " love nests" in 2004. The result was an epidemic of crow-caused blackouts in major cities around Japan: Between 20, the corvids stole almost 1400 fiber-optic cables from Tokyo power providers, and according to the Chubu electric company, crows are responsible for around 100 power failures per year in their facilities alone. Urban crows like to nest on electric transformers and will often use wire hangers or fiber-optic cables as building materials for their nests. Since the 1990s, crows have experienced a population boom in Japan, where-not coincidentally-delicious garbage is more plentiful than ever before. Why do they do this? Some studies suggest that the mass gathering is part of a survival strategy: The birds are learning about threats and seem hesitant to revisit any spot where they've encountered a dead crow, even if food is plentiful there. During this ritual, the live crows almost never touch the dead one, which rules scavenging out as a motive. The sight of a dead crow tends to attract a mob of a hundred or more live ones. When a crow dies, its neighbors may have a funeral. And some birds become regular nest assistants, providing aid to their parents for over half a decade. One study found that 80 percent of American crow nests surveyed had a helping hand. Other services they can provide include bringing food to mom and dad, or feeding their younger siblings directly. Juvenile birds are frequently seen defending their parents' nest from predators. During the winter months, they'll congregate with hundreds or even thousands of their peers to sleep together at night in a sprawling communal unit called a roost.Ĭome nesting season, a mated pair of crows might be lucky enough to receive chick-rearing help. For instance, American crows spend most of the year living in pairs (they usually mate for life) or small family groups. Like a lot of intelligent animals, most crows are quite social. Older crow siblings can help their parents raise newborn chicks. You can hear crow vocalizations here and raven vocalizations here. Only occasionally will a raven make a call similar to a crow's caw, but even then it is so deep as to be fairly easily distinguished from a real crow." "American crows make the familiar caw-caw, but also have a large repertoire of rattles, clicks, and even clear bell-like notes," McGowan writes, whereas common ravens have "a deep, reverberating croaking or gronk-gronk. And the birds' calls are substantially different. McGowan of the Cornell Lab of Ornithology writes on his crow FAQ page, ravens soar longer than crows, and you can see through their wing feathers as they fly (among other differences). One big indicator is size: The common raven is much larger, about the size of a red-tailed hawk. Telling them apart can be tough, but it is possible for eagle-eyed birders. In the U.S., when people talk about crows and ravens, they're usually referring to the American crow ( Corvus brachyrhynchos) and the common raven ( Corvus corax). Despite its informal name, the so-called Australian raven is more closely akin to the Torresian crow than it is to the common raven. But pervasive as these labels may be, they're not scientific and do not reflect the latest research. There's also a large-beaked outlier known as the rook, which was named after the unusual sound it makes. Mid-sized members of the genus are usually called crows, while the very smallest species go by the name jackdaws. Historically, the name raven has been given to several of the big-bodied Corvus birds with shaggy feathers on their necks. Colloquially, some of them are referred to as ravens while others are called crows, rooks, or jackdaws. To date, scientists have named 40 species. Members of the genus Corvus can be found on every continent except Antarctica and South America (although other close relatives live there). All crows and ravens belong to the same genus. Here are a few facts about these crafty corvids that might surprise you. But the birds are fascinating creatures, adaptable and brainy to an extent that's almost scary. In many Western cultures, they've historically been associated with death, disease, and bad omens reviled as crop-stealers by farmers, and condemned as nuisances by city dwellers.
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