Today we’re reblogging a remarkable article by Alyssa Frediani of The Raptor Trust. The original post can be found on the Delaware Valley Eagle Alliance webpage for Nature’s Newsletter on page 12 of the Winter Issue.
“Cr-r-ruck, cr-r-ruck!” The harsh, grating call of a raven breaks the morning silence at the Raptor Trust. The Common Ravens that reside at the Trust, Jake and Ray, are among the most vocal of the permanent resident birds here. Ravens have been recorded making over 20 different categories of vocalizations, which are used for social interactions, alarm calls, chase calls and fight calls. In addition to having their own “language,” ravens are skilled mimics. Jake and Ray are constantly amusing the staff and visitors with their wide array of calls, including popping
calls, croaking, knocking and even the call of a peacock!
The largest passerine, or songbird, ravens are clever, curious and have a commanding presence. They have an intellect that is on par with human children and great apes and have proven capable of solving complex puzzles. They have shown the ability to use tools in completing multi-step processes. They can remember faces and even specific voices for several years. Research has suggested that ravens build up a sort of social capital that is reciprocated over time. Favors in the form of preening, or aid in a fight, are given to ravens that are in good standing with each other. In our case, Jake and Ray certainly seem to remember who feeds them the most often and they have their favorites among the staff.
At the other end of the spectrum, they also remember those who have “wronged” them, in their eyes at least. The senior staff members who are responsible for doing wellness checks are not warmly welcomed when they enter the ravens’ aviary. Last fall I decided to carve pumpkins and hide treats for the ravens in them. I brought the pumpkins in and offered them to Jake and Ray, who promptly decided pumpkins were terrifying. They jumped around, calling out in alarm until I removed the pumpkins from their aviary. For weeks after the pumpkin incident, I could not enter their aviary without them calling warnings at me to stay away. Adult ravens, as smart as they are, develop a phobia of new things as they mature.
Ravens in general are very playful and young birds are especially inquisitive. They have been observed performing acrobatics in flight, diving and rolling in the air. One young bird was observed flying upside down for over a half a mile! They are one of the only animals known to make their own toys, in the form of broken off sticks. They will drop the sticks repeatedly and catch them mid-flight. They have also been observed tossing stones back and forth to each other. On the occasion that wild ravens come to The Raptor Trust, we have observed them passing sticks through the roof of Jake and Ray’s aviary, and the vocalizations they make to each other sound like they are having a conversation.
Historically, Common Ravens were driven out of the eastern United States, due to habitat loss and advancing civilization. They are a bird that prefers open and forested habitat, including high desert, sea coast, tundra, grasslands and sagebrush. More recently, they have been adapting to the growing human population and are moving back into rural and suburban areas. They have learned to scavenge for food in human garbage and unattended food and picnic items. They have even been observed undoing Velcro and unzipping zippers at campsites to steal food. Ravens are omnivores and generalists and will eat almost anything they can find including small animals, eggs, beetles, and fish. Our ravens eat a wide variety of food, including mice, quail, peanut butter, berries, melons, and mealworms.
Ravens’ intelligence makes them formidable predators in the wild. They have been known to work in pairs to raid the nests of seabirds. One bird will distract the parent while the other grabs eggs or babies from the nest. Their superior ability to raid nests is causing problems for species that are already at risk, such as Marbled Murrelets, Least Terns, Greater Sage-Grouse, and even Desert Tortoises. Ravens also seem to have formed a sort of partnership with wolves in the west. They have been observed following wolf packs and stealing from their kills quite frequently. In some cases, they have even been known to call out when they encounter an injured animal, alerting wolves to an easy kill. Ravens seem to be able to use their intelligence to put together cause and effect. They will investigate after hearing a gun shot in the area, presumably to find a carcass, but will ignore other similarly loud noises such as a car door slamming. Their hunting prowess means that they have virtually no natural predators as adults. Though their fledglings are vulnerable to predation from owls, hawks and eagles, the greatest threat to ravens is humans. Common Ravens will defend their young very aggressively against predators. They are usually successful at driving predators away and have been known to drop rocks on predators that venture too close to their nests. Their nests are very large, constructed from sticks and lined with mud, animal fur and grasses. The nest is generally 5 feet across and about 2 feet tall. They prefer to nest on cliffs, in trees or on man-made structures such as power-line towers, telephone poles, billboards and bridges.
Common Ravens are becoming more common in the eastern half of the United States. They are beautiful, large, silky black birds that are easy to identify. The telltale, echoing “c-r-r-oak” of a raven in flight is an ever more common sound in our area. In flight they are larger and more graceful than crows, but thinner with longer, narrower wings. They also have a long, distinctive, wedge-shaped tail, differing from the more fan-shaped and rounded tail of the American Crow. While Common Ravens can be spotted regularly in the more open areas of Sussex and Warren County along the Appalachian Mountain Range, they are sometimes found throughout the area, even in unexpected locations like landfills and around dumpsters