'I heard a barnacle'—how paying attention to nature's background noise can reveal animal secrets

During four days on Washington's Olympic Peninsula, I saw an Olympic marmot, a species found nowhere else on Earth; four bumblebee species working the same lavender plant; three western hermit crab species new to me; and five orcas slicing through the dark water off Ediz Hook. Any one of them could have been the trip's highlight.