In all they do, crows benefit from the company of other crows. These creatures' immediate families are their main social group, but they fraternize outside their own family unit, too. Crows tend to mate for life, moving on to other mates only when their original mate dies or is severely incapacitated.
Crows are social birds who spend their time in family groups known as flocks or murders. The groups start as small as two crows and grow to as many as 15, including mom and dad, the nonadult young and sometimes offspring from previous breeding seasons. Most young mature birds eventually strike out on their own to start their own families, but even crows have kids reluctant to leave home. Some crows have been known to stick with the murder for up to seven years.
When it's time to add to the brood, both mom and dad will work for a week or two to build a nest. It takes 18 days for mom to incubate her eggs; often during this period she'll be fed by her mate or one of her youngsters from the previous year. After hatching, the family adults will pitch in to help feed the chicks for the next month. It's normal for one or more young crows to stick around for the following nesting season -- or several seasons -- to help care for chicks. In addition to bringing food to the nest, crow co-op duties also include guarding the nestlings.
Socializing Outside the Family
The family group stays intact when it leaves its home territory, Migration serves as an opportunity to congregate with other crows. In the fall and winter, crows will gather in large numbers to roost. A single roosting unit might have fewer than 100 crows or it might have thousands -- or even hundreds of thousands. Though theories exist, what doesn't is a way to know for sure why crows sleep in such large groups. Theories include that doing so potentially protects against predators and weather, that the roost is well-located, such as near a large food source, and that it serves a social function.
Peace and harmony aren't major crow traits. Crows may fight other crows to defend territory or some other resource, or they may be protecting a mate. Family conflicts are typically short-lived and limited to a few pecks. Fights between different families can be long and potentially lethal.
Just as you, your cat and dog enjoy play time, so do crows. Crows have been known to grab objects, such as a small backyard toy, and entertain themselves by shaking and dropping it over and over. They've also been spied flying and climbing against a hard wind, then letting themselves be carried away by currents to fall towards the ground; they catch themselves and do it all over again.