He might have been a fish feeding in a stream while a small flock of birds passes overhead.

The pilot lowered the aircraft nose and the flock passed overhead.

This flock was probably just passing through, and won't be back.

A flock of birds was passing on its way south to wherever they spent the winter.

We were quiet for a long time, as the wind tangled our hair, and a flock of gulls passed overhead, calling among themselves.

On this morning several large flocks passed overhead but failed to come in.

However, when a flock is passing through a village the dogs walk calmly without paying attention to people.

"I was in my tree when a flock of harpies passed," he said.

He glanced up at the sky and watched a flock of birds pass overhead.

We were about to leave when a flock of crows passed overhead.