In celebration of Halloween, I write about ravens. It’s the spookiest bird I can think of. It’s not only the color. There is just something eerily intelligent about them. Indeed, ravens have one of the largest brains in the bird world.
I’m sure we learn valuable lessons by studying ravens, but come on, scientists, you’re just having fun, aren’t you? It must be an enjoyable challenge to devise intelligence tests for these birds and then watch them beat you at it. Biologists have fashioned all sorts of trials whereby the bird must retrieve a morsel of food by solving a puzzle or using tools.
Ravens are sneaky. Their bills are not designed to open the carcass of a dead animal. If they are the first to find one in the woods, they’ve been known to raise a ruckus, attracting other scavengers that are then able to tear open the hide. The ravens merely wait their turn or opportunistically dash in for a chunk. A study in Wyoming revealed that ravens will fly toward the sound of gunfire, hoping that a successful hunter will leave entrails in the woods.
Ravens cache food in anticipation of leaner times. Craftily, they also watch each other, and they remember where their friends stashed the chow, so they can steal it. However, the ravens are aware that they can’t trust each other, and they work harder than other birds to find safe hiding places, often travelling farther than necessary. They even pretend to cache food, trying to fool onlookers.
Ravens play. They’ve been witnessed sliding on snow, teasing other animals and somersaulting through the air. There are accounts of ravens flying upside down for over half a mile. Juvenile ravens are particularly playful, and all ravens are fascinated by shiny things. Over time, adult ravens become suspicious of anything new and unexpected.
Chalk one up for intelligence, ravens are the most widespread members of the corvid family. They are found throughout the northern hemisphere. Corvids include ravens, crows, jays and magpies. Ravens are omnivorous, eating grains, berries, insects and animals, both alive and dead. They can eat garbage and the undigested seeds found in manure. Ravens can find food in cold climates where humans barely exist, yet coexist comfortably with humans in populated areas. Roadkill is a favorite food, something that humans make in abundance.
Raven numbers plummeted in the early 1900s, partly because of habitat loss, but mostly because farmers used poison and shotguns to keep them away from crops. Raven numbers have not recovered in the southeastern United States, though northern ravens are expanding southward along the Appalachians. Raven populations in the west have vastly increased, with a range that extends from the arctic to Mexico.
Ravens are not as sociable as crows. It’s unusual to see more than a single family unit together. Mated pairs often travel and forage together, and they remain devoted to their offspring for much of the year. Young birds begin courtship behavior quite early in life, even though they are not likely to breed for several more years.
In groups of unrelated birds, ravens become quite quarrelsome. They aggressively defend nesting territories, reducing competition for the food sources they will need to feed their families. Yet, when a raven in winter finds a carcass too big for one bird, it will often call others to the feast. The finder benefits from this altruism because someday it, too, may be called.
All of these complex social interactions create the need for a big vocabulary. Ravens are famous for the variety of sounds they make, including the ability to mimic. Birds have been taught to imitate human speech, including multisyllabic words such as nevermore. In the wild, biologists have documented up to thirty different vocalizations, plus a series of wing flaps and bill clicks, all of which help them to sort out their relationships with other ravens.
We’ve got lots of ravens in Maine, but we have even more crows. It can be difficult to tell them apart, even though ravens are much larger. Under ideal conditions, the differences are apparent, but conditions are never ideal. Wind and sun can play tricks. A bird can look big when observed from below, but smaller when seen from the side. Ravens have huge bills and diamond-shaped tails, but these field marks are easily obscured from many viewing angles.
I’ve been seeing a lot of ravens lately. Child-rearing is done, winter isn’t here yet, and they are feeling particularly playful. Happy Halloween.
Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.