In what way does the passage suggest that penguins were compensated for losing the ability to fly?

Well, honey, those Flightless Birds got the short end of the stick, but at least they got a consolation prize in the form of being expert swimmers. The passage implies that penguins were compensated for their inability to fly by evolving into fantastic underwater acrobats, using their flippers to zip through the water at impressive speeds. So, while they may not soar through the skies like other birds, they sure know how to make a splash in the ocean.