Bourne's Pond isn't actually a pond the way I understood one growing up, because it opens to the Atlantic Ocean. But here in MA a pond is defined a little differently - especially on the coast. Here a pond is a body of water smaller than a lake, usually fed by a stream, but mostly still.
Bourne's "Pond" has tidal action and lots of coming and going of water, but it is 2 miles from the top inlet to the bottom ocean outlet so maybe some of it moves more than the rest. We canoe out here and catch/release a few fish every now and then.
The swans come here in great numbers. This morning I counted 25. There have been more so that isn't a record. Here are some pics. There is a lot of bird watching on the Cape, and Falmouth is a great place to see birds.