Winter crow conventions cause controversy, sometimes fun

In the summer or fall you might see a few circling and diving: Caw! Caw! Caw! Bark! Bark! Bark!

That bark part is only if they are teasing a dog.

But in winter, crows form enormous roosting groups with hundreds or even thousands of birds that perch, sleep, and scavenge together.
These groups are called a murder of crows, although researchers stick with the less-poetic word, flock. Their immense winter gatherings are usually near a city, where they often causes commotion and controversy.

One famous example comes from Seattle where 150,000 birds decided to roost at the University of Washington campus. The group was so big, the trees drooped with their weight. Hundreds of crows also lined up in neat, but creepy, still rows on the tennis courts, described by one observer as crow zombies.

This mass of birds causes a lot of noise and mess, as thousands of birds leave daily droppings and feathers. Sometimes only hazing will make the flock roost somewhere else, but it is usually nearby, according to nature.org.

Still, the birds are fascinating to watch as they preen each other and caper around the roost. Crows maintain family relationships, sometimes for their entire 14-year lifespan. They also mourn their dead. The entire roost might show up to visit a dead member, vocally sounding distress and looking for predators. They can be aggressive and dive bomb if a fellow crow or fledgling is on the ground or injured, according to live science.org.

Like their cousin, the raven, they can solve problems, recognize human faces (and hold a grudge if the human is mean to them). Ravens are bigger and don’t hold winter parties. So if you see a massive group of black birds, they are probably crows.