Crows

Crows roost in the trees in the First Street Common in Pittsfield.

Q: While I was driving past the Common Park on First Street in Pittsfield around 5 p.m. a few days ago, there were many hundreds of black crows in the trees just before the bridge. I never saw a spectacle like this. Can you explain?

— Patrick M., Great Barrington

A: Most of us have seen or heard of crows chasing (mobbing) a hawk, eagle or owl during the daytime. While kayaking, I once watched crows mobbing a pair of bald eagles building a nest along the Woods Pond shore in Lee. The crows badgered the eagles so vigorously and persistently that the couple gave up and abandoned the nest and did not return.

SAFETY IN NUMBERS

Thus, crows have lots of dangerous predators. And at night, they protect themselves from these predators, real or imagined, by gathering together at night. Sometimes by the dozens, sometimes by the hundreds, other times by the thousands. Sleeping together means more individuals to provide safety.

Individuals in that flock in The Common come from some distance. I was walking near Crane Avenue the other afternoon around 3:45 p.m., and I noticed crows heading in small numbers of up to 20 or so flying in the direction of where The Common is. I would not have given it too much thought, but I also saw that roost while riding with my wife along First Street.

The following afternoon, I photographed it. I arrived in time, about 4:30 p.m., to watch the crows gathering in various trees called pre-roost or staging locations in The Common and along First Street and across in trees near the old Eagle Building. By 5:10 p.m., they had vacated those trees and joined the main roost that included, by then, the full length of trees along the train tracks bordering The Common as far as I could see. In short, sleeping in large groups means there are more crows to provide flock safety should something happens at night. How they sleep with all the commotion, I do not know.

OTHER SPECIES GATHER FOR SAFETY

If not from predators, from the winter chill.

Can you imagine a crowd of chickadees or bluebirds huddled together in a box or even an old nest in a sheltered location on a frigid February night? Well, they do, in fact, some birds, especially those that nest in boxes or cavities in summer, will roost on cold winter nights in nesting boxes or other sheltered places.

As summer nesting boxes are used, you can construct better boxes for winter nesting: A roost box can be built to accommodate birds looking for a warm place to spend the night. There are few rules for making roosting box, except that it can be several times larger than a nest box with the hole near the bottom as heat rises rather than near the top as usual for summer boxes. And perches or shelves within allow accommodating more birds.

For chickadees and smaller birds, the hole can be about 1 and 1/4 inches; while bluebirds, hairy and downy woodpeckers prefer a hole one 1/4- to 1/2-inch larger. Also, if the box is made primarily for bluebirds, place the hole midway up as the birds may just huddle together on the floor.

Fasten the box in a tree or on a pole, and if possible, with its back to the prevailing winds. Bluebird boxes may be hung low — about 6 feet from the ground. Other birds may prefer the box about 12 feet up. For larger flocks of bluebirds, several boxes may be made and placed within a yard or so apart.

READER COMMENTS

I just watched a mourning dove drinking water from a dripping icicle! The icicle was dripping on the deck railing, and the dove was drinking from the water as it hit the railing. That was a first for me. Actually, my indoor kitty was the one who spotted the dove drinking. He was enrapt at the window, so I went over to see what he was watching, and voila. I'm done knocking down icicles after seeing this!

— Nancy S., Pittsfield

Isn't a flock of starlings a murmuration? Of crows a murder, of swans an exultation, of flamingos, a flamboyance? Some of my favorite group terms or collective nouns. I so enjoy your column.

— John McC., North Adams