March 8, 2015 A bird brain worthy of respect: Crows
The common crow is anything but ordinary. Take a few moments to observe this dark-winged beauty and you’ll be amazed.
There are about 45 species of crow worldwide known by a variety of names, including ravens, jackjaws, rooks and crows. They all belong to the genus called corvus. Their plumage is mostly glossy black, but some have streaks of white.
These fascinating birds are loud, daring, gregarious and clever. And they are toolmakers.
They nest way up in the treetops of both deciduous and coniferous trees. Nests are built close to the trunk, providing a vista of the surrounding landscape.
Mating crows will often remain together for years and some until parted by death. Most of the offspring will leave the nest after a couple months never to return. Some, on the other hand, remain, assisting in co-operative breeding.
I’ve observed this in both Banff National Park and Sequoia National Park and its been recorded elsewhere in the United States and New Caledonia.
There are about 10,000 known species of birds on Earth and most tend to rely on shyness and their coloration for camouflage as survival mechanisms.
Not true for any of the corvus clan. At times they seem absolutely fearless, particularly when chasing bald or golden eagles. On other occasions, they’ll pick up and drop stones, pinecones or sticks on predators or people they come in contact with.
The common crow will usually live for about seven years, although some have lived as long as 14 years in the wild.
If crows don’t rely on camouflage or stealth to make a living, how have they successfully come to inhabit the globe?
In the late 1990s, New Zealand researchers working in the forest of New Caledonia discovered crows making tools. The birds whittled sticks to make hooks and inserted the tools into tree bark to spear insects.
Toolmakers such as chimpanzees, orangutans and elephants, some ant species, some woodpecker finches from the Galapagos, dolphins and human beings are all social animals and insects.
Crows are intelligent animals that are able to solve problems. For instance, as Aesop related in one of his fables, a very thirsty crow was perched atop a water jug, but the water level was too low for its beak to reach. The clever crow began to drop pebbles into the jug, forcing the water level to rise until it could drink the water.
At Oxford University, a New Caledonian female crow clearly demonstrated a basic understanding of physics. In order to obtain her favorite food — a pig’s heart — she had to pick from several tools of different diameters to successfully poke a stick through a small hole in a plug. Betty, the crow, always selected the thinnest stick in every trial.
In another experiment, having never seen wire being bent, Betty quickly made a hook, placed it down a tube and retrieved the food.
The speed at which Betty performed the task was remarkable. No other animal including a chimpanzee has displayed problem-solving like this.
Quite simply, crows are toolmakers extraordinaire.
Crows are emotional animals, too. They react to hunger and invasion by vigorously vocalizing their feelings. They display happiness, anger and sadness.
Crows are considered song-birds and posses a deep repertoire of melodies. And, like humans, the more melodious the song, the more soothing the effects.
Crows have an excellent memory. They’re masters at stashing food in many caches, moving it sometimes two or three times, and remembering exactly where they placed it. In fact, for their size, crows have the largest brains of all birds except some parrots. They even surpass most mammals.
Their brain-to-body ratio is equivalent to that of a chimpanzee and amazingly, not far off that of a human’s.
As temperatures on Earth continue to rise due to the burning of fossil fuels, few organisms will benefit except for the deadly mosquito.
Crows and humans share one other similarity: we’re both highly susceptible to the mosquitoes carrying the potential fatal West Nile virus spreading throughout North America.
Earth Dr Reese Halter’s latest book is Shepherding the Sea: The Race to Save our Oceans.
Text © by Dr Reese Halter 2015. All rights reserved.