For the Birds Radio Program: Ravens and Crows
Laura talks about the two big black birds that confuse so many.
Recording of a Common Raven)
Ravens are heading south in big numbers now, migrating along the North Shore and Hawk Ridge in Duluth. The problem is, nobody’s exactly sure where they’re headed for. There are no large concentrations of ravens in southern or central Minnesota or Wisconsin in winter, and states south of ours don’t report many ravens period. Maybe there’s a group of ravens that fly over Duluth in a circular pattern just to confuse our counters, or maybe they all duck out at some Holiday Inn until spring. Quite a few do spend the winter in Duluth and along the South Shore. They take over at the dump, and can often be seen picking at garbage dumpsters behind restaurants all winter–pinch hitting for the ring-billed gulls which go further south.
Many crows migrate, too, though like ravens some individuals remain in the Northland all winter. People along the shores of lake Superior and along the Brule River in Wisconsin are lucky–they can see both crows and ravens all year. Ravens are more birds of wilderness than crows, especially during the nesting season–we seldom see ravens in Duluth in summertime, but crows have nested right in my backyard. Ravens become more common in the city in winter– many years they outnumber crows on Duluth’s Christmas Bird Count.
Field guides make it sound easy to tell crows and ravens apart, but this time of year there are some difficulties. Normally yu can tell them apart by the tail—the central feathers of a raven are longer than the outer ones, causing a wedged appearance. But this doesn’t work when the birds are molting their tail feathers, which many ravens are doing right now. If the central feathers are just growing in, the tail can appear as rounded as a crow’s. Ravens are much larger than crows, but since they seldom fly in mixed flocks, this doesn’t help much, unless a neighborhood crow is dive-bombing a flock of overhead ravens. If you see a large black corvid flying silently with its beak open, it’s a raven. If it caws, it’s a crow. If the voice sounds more like a croak, it’s a raven.
Ornithologists studying crows have identified at least 23 different calls, each with a different meaning. The assembly call, given when one crow discovers an owl, attracts other crows to the scene–then they all mob the owl. Thirty years ago an American ornithologist exchanged recordings of crow assembly calls with some French ornithologists and discovered that this assembly call is readily understood and responded to by French crows, but that the alarm call of American crows is ignored by the French birds. The implications of this for French-American political relations is still not known.
Ravens, which are considered to be even more intelligent than crows, may actually speak with intention to one another, and as it were, call one another by name. Ravens also definitely have a concept of number. In 1951 an ornithologist showed that a raven could count at least up to six.
Some people don’t like crows or ravens at their feeders, but that’s a point of view I definitely don’t share. Extremely lucky people attract them with sunflower seed, but I use Purina Cat Chow to bring in the crows in my neighborhood. They also like peanuts.
(Recording of a Common Raven)
This is Laura Erickson, and this program has been “For the Birds.”