Shipwreck means a sudden excitement/event. Based on the movie, it could mean when Soren and his brother fell out of the tree. Or it could mean the sudden event when they were saved and carried away by the other owls at the beginning of the movie.
Also, it could mean brought to a foreign place by the owls and left there, stranded and unable to find a way back.
Dictionary definition of shipwreck: ship destroyed and people are stranded on foreign land.