I have recently become fascinated by the communal roosting habits of birds. Lest you think I’ve gone all science on you, I usually do this on my evening walk with no more equipment than a willingness to stand still and watch. When I lived in the mountains, I noticed birds in trees, but rarely observed how they got there. Coastal birds, however, make a production of this nightly event.
I first noticed these rituals in a spectacular setting. I was returning to Cedar Island from Ocracoke on the 6 pm ferry. I recommend this trip. On top of the ferry, you can sit in a bowl of sunset that quiets your mind, softens your heart, and washes you in peace.
As we passed a sandy spit of land just off shore from Ocracoke, I noticed that the air was crowded with white birds – shore birds, whose identification I did not know. A flurry of birds, close and far away, raced toward the sand bar at breakneck speed while calling out, “I’m coming. I’m coming.” It was as if someone was taking roll call and any latecomers would be locked out. The flying birds filled an area that took 20 minutes to pass in the ferry.
Some birds were pure white; others wore additional brown patches. They distributed themselves by coloring to the left and right of the island. Each newcomer located his or her place and landed in less than a heartbeat to join the trembling carpet of squawking birds.
When we moved to our new house, I discovered that egrets - Snowy. Great, and Cattle – roost around a small lake near the end of our street. When I walk the dogs around 5 pm, the white birds are already coming in for the night.
These birds drift in leisurely, by ones or twos, like men dropping into the local bar after work. I believe they gather in what’s called a staging area nearby because I never see many birds in the air. They wait their turns. It’s quiet, and after a few minutes I am astonished to see how these great birds have filled the trees. A study in Mexico found that Snowy and Great Egrets crowd out other species from the tops of trees – a safer place to perch. I believe that’s true for my flock, and it’s odd to see those big boys hunkered down on spindly limbs.
As each egret arrives, he arcs across the lake and floats to a pinpoint landing in the roosting site. Upon his arrival, the crowd croaks in unison, as if to say, “Hello, Fred,” readjusts their wings, and returns to nursing their beers. They repeat this for each landing bird.
The roosting habits of vultures are, strangely enough, like a ballet in several acts. I first noticed them circling over the woods across the street, just as they do when they’ve located prey. I thought it unusual to see them in the same place for several successive evenings.
One day on my morning walk, I saw the vultures sleeping in two dead trees: they are not especially early risers. The next evening, when I saw them circling, I went over to watch. Vultures are in no hurry to roost. They act as if they are checking out a new accommodation each evening and trying to get a consensus about its suitability.
They first circle around the trees in a wide path, like jets in a landing pattern. You can see their dark forms approaching from a distance, much like the sea birds. Seldom flapping their wings, they catch the air in graceful swoops.
They circle for a while, then land in their staging area – the woods next to the dead trees. Black bodies perch tentatively among the trees while their compatriots continue to circle.
In a while, one or two will fly over to the roosting place. No one appears willing to move over, so the newcomers touch lightly on this spot then another, and then settle hunched over like the egrets. I think they are just checking out the beds as sometimes they return to the landing pattern for another try. Others then move from the staging area to the roost. I have never been able to make myself watch long enough to see all the birds settled, but their sleeping forms in the early morning suggest that they do.
Vultures, like their names, are not pretty. Their work is not pretty, but their coming to roost is careful, graceful, and well worth watching.
I saw a question posted on the Internet, “Why do birds go insane at night?” All this sound and fury, so different from their purposeful behaviors during the day, does look kind of insane. Researchers believe that their urgency and the ruckus they make is how communally roosting birds call their members home to a safe place and the warmth of the flock.
Not all birds roost communally. Some of them, like humans, are loners and brave the night alone. I wouldn’t care to sleep alone in a tree vulnerable to cold and rain and predators that hunt. I prefer to find my way home at night, where it is safe and warm and someone will scoot over and call out, “Come over here. We saved you a place.”
