Jumat, 20 November 2020

12 Fascinating Facts About Crows

Crows often get a bad rap. 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. But the birds are fascinating creatures, adaptable and brainy to an extent that's almost scary. Here are a few facts about these crafty corvids that might surprise you.

1. All crows and ravens belong to the same genus

Members of the genus Corvus can be found on every continent except Antarctica and South America (although other close relatives live there). To date, scientists have named 40 species. Colloquially, some of them are referred to as ravens while others are called crows, rooks, or jackdaws.

Historically, the name raven has been given to several of the big-bodied Corvus birds with shaggy feathers on their necks. Mid-sized members of the genus are usually called crows, while the very smallest species go by the name jackdaws. There's also a large-beaked outlier known as the rook, which was named after the unusual sound it makes. But pervasive as these labels may be, they're not scientific and do not reflect the latest research. Despite its informal name, the so-called Australian raven is more closely akin to the Torresian crow than it is to the common raven.

The common raven is much larger than the American crow, about the size of a red-tailed hawk.

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). Telling them apart can be tough, but it is possible for eagle-eyed birders. One big indicator is size: The common raven is much larger, about the size of a red-tailed hawk. It also has a more wedge-shaped tail. As Kevin J. 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). And the birds' calls are substantially different. "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. 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."

You can hear crow vocalizations here and raven...

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