Blue eyes, caramel wings and other crazy facts about crows
Kaeli Swift specializes in corvid thanatology (translation: stuff crows do when they die). A PhD candidate at the University of Washington with a knack for photography, herblog captivated us. So we invited her to drop some knowledge about some of our most mythologized Seattle neighbors.
Why does that crow have blue eyes?
Despite being roughly the same size as their parents, baby American crows have bright blue eyes. The eye color changes to brown as the crow matures over the summer.
Another feature to look for is a bit of pink at the corner of the crow’s mouth, called the gape. Although not always pink, a brightly colored mouth is a common feature among baby birds. It helps signal parents to feed them.
Knowing how to recognize and avoid their babies is crucial to coexisting with crows during the breeding season.
It is not abnormal for crows (and many other bird species) to leave the nest before they can fly. Unfortunately, well-meaning people often whisk them away to rehab facilities.
Abducting a baby crow is not advisable, considering crows remember faces (keep reading to learn more about that study).
Not all crows are black
Most American crows are black, but every once in a while one of them breaks the mold.
The most common color abnormality is leucism, which is a lack of the dark pigment producing melanin, manifesting in one or many white feathers.
More rare are “caramel crows.” What specifically causes this strange color mishap is still a mystery to science but probably has to do with the expression of different types of melanin in the feathers.
Color abnormalities can turn a crow into a target for predators or its peers, but this bird is doing very well in its south Seattle neighborhood. It had three all-black fledglings with its mate this past year.
One sure sign you're looking at a raven, not a crow: Ravens have specialized throat feathers called hackles, which almost look like beards. Ravens articulate these feathers in a variety of displays.
What's with the bracelets?
You may have noticed crows around Seattle with colored bands on their legs. They are most common around the U-District, South Lake Union and First Hill. These birds were banded more than ten years ago as part of a facial recognition study conducted by Dr. John Marzluff at the University of Washington.
Marzluff and his team were able to demonstrate that crows who experienced something scary at the hands of a person (being trapped and banded) later remembered and scolded that person.
The birds also passed on this knowledge to other birds, including their offspring. Later research by Kaeli Swift showed that they can also learn and remember people they see handling dead crows.
The next time you see a banded bird, tip your hat to them for the role they’ve played in advancing science.
Ever see a crow's knee?
Many people are under the impression that birds’ knees bend the opposite direction as ours, but this is not the case! The exposed joint you see is more akin to the human ankle. Their knees are simply hidden from view under their feathers.
No guacamole, please!
Human garbage (meat, grains and veggies) account for about 65 percent of a crow's diet in urban areas. In wildland areas it’s roughly split between garbage and invertebrates. That said, they shouldn't eat everything. For example: they can't eat avocados.
Avocados are toxic to most birds, and many other kinds of domestic animals. In birds, a molecule called persin that is found in avocado can cause heart tissue damage, difficulty breathing, lethargy or even death.
Story produced for KUOW by Bond Huberman