What do birds do at night? It’s clearly a question people find intriguing.
But you probably already know the answer even if you don’t know much about birds. Most birds are diurnal, so like most of us they sleep at night. And like us, they usually tuck themselves away somewhere safe and sound. In the deep cold, some birds will even roost together for warmth, pressed together side-by-side. Here in the city, you may have experienced passing by an ivy-covered wall or a thicket of evergreen that is absolutely howling with bird sounds near sunset: these are House Sparrows getting ready to hit the hay. They’re aren’t necessarily all pressed together in a row i this case, but they are sharing the protection of the foliage, and the protection of the group: there are more alarms to sound should trouble brew.
A night roost of hundreds of crows is a pretty spectacular sight, or should I say sound? Even after they’ve had their discussions and debates, there’s rustle and bustle. We don’t get this in the city, but I’ve seen Common Grackle after Common Grackle slip into trees at the Plaza Hotel just south of Central Park at twilight.
But not all birds roost together at night. Most probably don’t. Hawks for instance. Why, you may ask, would a fierce hawk worry about being out of sight at night? Take a look at Julie Zickefoose’s post on finding a hawk foot in an owl pellet.
Nearly two weeks ago, birder friends who live in Park Slope, Brooklyn, told me about the Accipiter roosting in their backyard. It’s been there every night since. The bird arrives about half an hour after sunset and leaves more than an hour before sunrise. Suave hosts, they had a few of us over for “cocktails and roost” the other night.
I believe this is a Cooper’s Hawk (Accipiter cooperii). Within just a few minutes of its arrival it becomes really quite hard to see beyond a dark shape. The first shot above was taken with the “hand-held night shot” feature. The second was actually taken earlier, with the standard PhD (Push here, dummy) feature. The tree is bare, but drooping with seed pods: it’s a Catalpa.
The backyards of a rectangle of row houses are curious conglomerations of spaces, habitats, and trees. You’re apt to find someone who feeds the sparrows and pigeons and rats in such spaces. And where there are gatherings of birds, bird-eaters are sure to appear.
A correspondent recently sent me a picture of another Accipiter in her backyard, which is also in Park Slope. This one looked like a Sharp-shinned Hawk (A. striatus). It had some very white patches on its back, which should be distinguishing. The two Accipiter species are notoriously hard to differentiate. There’s a strong sexual dimorphism in both species: females are substantially bigger than males. So, while Sharpies are generally smaller birds, the female Sharpie is as big as the male Cooper’s. Male Sharpies, on the other hand, are quite small: the length range for them starts at 1″ more than a Blue Jay. Generally, Sharp-shinned Hawks prefer woodlands while the city mostly sees Cooper’s, but these are loose rules.The night is full.