The idiomatic meaning of this strange saying is to get one’s affairs in order, to get organized before some big event, like a trip around the world.
Some waterfowl species really take this idiom to heart: they swim in a row, fly in a row, walk in a row, even stand in a row.
Do you wonder where these strange idioms come from? After watching some ducks evade my attempts to photograph them, I started to wonder whether this idiom originated from watching birds behave, or from some other source.
Wisegeek.org and word-detective.com had some thoughts on the subject. The bottom line is that the expression probably originated from sports games, specifically bowling, shooting, and pool. Early bowling pins were short and squat and were called ducks. Hand-setting of the pins after each frame was therefore called “getting the ducks (pins) in a row”. Early carnival games often featured sitting or flying ducks placed on a conveyor belt that had to be perfectly aligned (in a row) for the shooter to topple them with an air gun. Duck is also a term used in pool for a ball that is sitting right in front of a pocket — i.e., an easy shot. Thus, to have one’s “ducks in a row” was to set up easy pool shots. So take your pick for an origin of the term.
The common behavior of waterfowl species to form a line, rather than clump in a ball like a school of fish might do when threatened, seems to have some selective pressure driving it. I have no idea what that is, but it’s interesting to contemplate why it happens. Would a bird be safer in the middle of a line? Do lines provide greater energy efficiency?