Crows fill important niche

Caw! Caw!

The sound of a crow is not the melodious song we listen for at bird feeders. Nor is it usually considered a beautiful bird, but a crow makes up for its lack of appealing qualities with its intelligence.

American crows are members of the corvidae family, along with ravens, jays and magpies. Crows usually mate for life, work together to raise families, roost together in large numbers, and are year-round residents of Colorado. Offspring often stay with their parents for several years before going off on their own.

While many other species are endangered, crows are doing fine. They have adapted well to living with humans and eat just about anything. Most often seen as pests, crows are known for stealing food, pestering other birds and animals, and eating crops.

Sometimes benefits are not as obvious.

Crows vs. Ravens

How to tell a crow from a raven:

Crows: About the size of a pigeon, crows’ tail feathers open straight across.

Ravens: Similar to a hawk in size, ravens have a larger, thicker beak, a deeper “caw” and tail feathers that fan out in a wedge. Ravens are not seen as often in urban areas.

Ravens have also been observed and studied, exhibiting many of the intelligence and problem-solving skills of crows. People have watched ravens fly above predators, waiting for them to make a kill, or perhaps even alerting predators to prey nearby. One of the reasons may be that predators open up a carcass so ravens can gain access to the meat.

A study in Ontario, Canada, a few years ago found that crows ate a significant number of European corn borers, creating fewer problems the next growing season than in fields not visited by crows.

If you have ever been fussed at by crows, consider whether you may have treated them badly in the past. A 2008 study at the University of Washington tested crows’ ability to recognize individual humans and associate behavior with those particular humans.

Using different types of masks, the researchers discovered the birds not only recognized humans who wore masks that represented previous bad behavior, but also seemed to share that information with other crows, inviting them to help mob the masked researcher. In addition, they retained the memory when encountered years later.

New Caledonian crows are known to use twigs as tools to retrieve food from crevices. In 2002, Oxford University zoologist Alex Kacelnik gave a New Caledonian crow the challenge of retrieving a bucket of food from a tube. When the crow could not pull the food out with a straight piece of wire, the crow bent the end of the wire into a hook and then pulled the bucket out.

Past studies in Japan and a popular YouTube video show crows dropping nuts on roads so that cars will crack them open.

In fall and winter, crows often roost together in large numbers. One of the largest roosts — in Fort Cobb, Okla. — was estimated at 2 million.

Roosts or small groups of crows are often seen in urban areas. Dr. Kevin McGowan of the Cornell Lab of Ornithology believes that crows may choose urban areas for protection from people (who can’t shoot crows in town), safety from predators (especially great horned owls and other raptors), warmth, more artificial light and large trees to roost in.

Crows are also good survivors. McGowan’s webpage notes that only about half survive their first year, but if they do, crows can live 17 to 21 years in the wild. Researcher and inventor Joshua Klein highlighted the problem-solving skills of crows when he presented a study at the 2008 Technology, Entertainment and Design Conference in Monterey, Calif.

Klein created a crow vending machine. He placed a mixture of peanuts and coins on a feeding tray. Squirrels, seagulls, crows and other birds came to feed on the peanuts. When the peanuts were removed, the birds would sometimes accidentally knock a coin into a slot, which then produced a peanut. Later, all peanuts and coins were removed.

While squirrels and seagulls simply checked out the machine and left, crows looked for stray coins nearby and inserted them into the slot to receive peanuts.

Klein believes that crows could be taught to help people — like picking up trash after a concert to receive a food reward. It seems that people are just beginning to understand the intelligence that lurks beneath those feathered heads.

Maybe there’s more to what crows are saying than just “caw, caw.”

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