Here are the short-billed dowitchers.
If these are the short-billed, how long is the bill on a long-billed dowitcher?
Here are long-billed dowitchers.
Good luck telling the difference.
There are some subtle physical differences. Long-billed is a little chunkier, but the best clue is habitat. Short-billed prefers salt water. Long-billed prefers fresh water. Mostly.