Since You Asked: Crows flock together for many reasons
Every evening around 7:15 crows (lots of them) fly northwest to what I can only imagine is a communal destination. Do you have a clue as to what this behavior means? Is it normal for crows to congregate in this way?
— Maxine S., Ashland
They do this because they like to get together, Maxine, and share stories about what happened during the day.
Crows are extremely social, and gather in roosts to share information about food, keep warm and ward off predators. Some of these roosts attract astonishing numbers of birds.
"In the Company of Crows," by John Marzluff and Tony Angell (Yale University, 2005) notes that more than 2 million — yes, 2 million — crows have been seen roosting together in Oklahoma. What this says about Oklahoma, we're not sure, but it confirms that crows will travel long distances to roost together for the evening.
Marzluff and Angell observe that this communal behavior is a cultural attribute.
Young birds learn about roosts from their parents, and crows that don't know where the group is spending the night find out by following those who do.
There's safety in numbers, too. If a pair of crows spend the night in some isolated tree, they're more vulnerable to predators.
Researchers have learned that family groups split up in the roost, increasing the chances of preserving at least some of them.
They reconnect in the morning, and head off looking for the nearest corn field, dump or parking lot in search of delectables.
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