I got home a few minutes ago as the last little bit of daylight was still in the sky, and the neighbor’s trees (maples and spruces) were full of hundreds and hundreds of crows. way up in the very tops of the trees. It was an exceedingly cool sight, if a little Alfred Hitchock-esque. (Me to husband: “Wow! That is so cool!” Husband to me: “Yeah, that’s what Suzanne Pleshette thought, too.”)
So, anywhistle, why were the crows congregating? They aren’t migratory, are they? I think I’ve only seen them do this in the fall.
They’ve been out foraging all day and are headed home to the suburbs (your neighborhood) where there are lots of nice trees to roost in.
I used to live in downtown Sacramento CA, and they have a similar nightly invasion of crows arriving to roost in the trees in the parks that line the American River on the west end of town.
They are social critters. They like to sit around and shoot the shit before and after their 'work day." Crows flock together in large numbers at night. In the morning, they fly off in groups to foraging sites. The groups land, split into smaller groups, which land and separate again. In the evening hours, the process reverses. The come together in small groups, socialize, fly to another meeting point, socialize, fly onto another rendezvous and so on.
How big were these birds? the reason I ask is that crows are freaking huge, whereas starlings are smaller (about the same size as a robin) and also form huge flocks. It’s interesting to watch them flock on a wire, then wheel around a moment and come to light again a short distance from where they were.
These were very clearly crows – freaking huge and making their unmistakable cawing sound. I definitely recognize a starling when I see one, and, disgusting as they are, do enjoy watching that wheeling behavior.
When I was in California (near Sacramento) crows would roost in a group of trees nearby. Every day at dusk, like clockwork, you would see scores of crows flying in from all directions to hang out in these trees. I used to love to go watch them roost.
I read once that the saying “as the crow flies” comes from people observing crows flying to a nightly roosting spot in the plains states.
And my own experience gives creedence to this. I used to frequent an outdoor hot tub around sunset. Without fail, there was always a steady stream of crows all headed in the same direction that lasted for over an hour.
Sorry, over the past few days I was migrating myself and wasn’t able to respond to this. However, many of the reasons for crow communal roosting have already been touched on.
Some of the reasons crows and other birds may roost together at night:
Protection from predation. Predators that try to attack an individual may be mobbed and driven off by many member of the group. Also, a few members of the group are likely to be awake at any time of the night, and can give give warning.
Information sharing. When birds take off in the morning, those that found food the previous day may be followed by others. (And possibly can be distinguished by their quickness in leaving in the morning.)
In cold climates, birds can huddle together for warm during the night.
There’s a parking lot in a hollow across the street from the place I worked. In most winters, it would be a crow roost for a few weeks. With the cold wind out of the west, the warm air from the huge factory would curl into the protected parking lot. Thousands of birds would spend the night on the ground. It was literally impossible to walk across the lot without stepping in crow poop. Some night shift workers would drive fast through the flock, killing dozens of them. That’s a federal crime.
The plant had to walk a fine line. They had propane cannons and other noisemakers to spook the birds, but there’s a migratory bird treaty that prohibits “molesting” them. Employees, meanwhile were filing health complaints about the guano.
My mechanic’s shop, a block away, has a row of tall trees. In the morning and late afternoon, it was too loud to converse without shouting. He tried firecrackers, but the cops came around to tell him to stop.