That was the sound that registered in my ear after I saw a large, streamlined, gray-brown blur speed past the kitchen window, twist in mid-air, then disappear through the small opening in the wisteria arbor.
The small birds in and around the feeder scattered, but small movements in the thickly-foliaged wisteria bush gave away their hiding place.
A young squirrel froze in place on the deck rail.
After a few minutes, the birds emerged cautiously from the wisteria, the chipmunks came back from under the deck, and the squirrels resumed their efforts to get into the feeder (they can’t).
What was it?
A young Cooper’s Hawk had come for dinner, but didn’t stay long – it ordered take-out.
We’ll have one less House Sparrow tomorrow. That’s OK; they are an invasive species anyway, we have far too many of them, and they are perfect hawk nibbles.
By the way, if you think that a Robin is "nicer" than a Hawk because you think it doesn't hunt and kill prey, watch closely next time a Robin is hunting earthworms on your lawn. Robins are stealth hunters, too, listening carefully for the worms and snatching them from their underground tunnels. Any bird that eats any living thing is a hunter. Hawks just do it more noticeably and with considerably more panache (naturally) than many other birds.
Hawk Haiku *
Silent gray-brown blur–
Birds at the feeder scatter:
Cooper’s Hawk took one.