In a flock of birds, why is one side of the 'V" formation always longer than the other?

Question

In a flock of birds, why is one side of the 'V" formation always longer than the other?

Answer 1

I imagine it's because they'd have to really be synchronized to be exactly even.  As in, the spaces between the birds vary, as some birds get tired, some birds speed it up a little.  Plus if there happens to be an even number of birds, it will always be lopsided.  For example if there are ten birds in a V, then one is in the front, leaving five on one side and four on the other.  Many species of geese mate for life, so there would usually be an even number.  These are all just my best guesses, though.

Answer 2

Because there are more birds on one side!

Answer 3

Pure mathematical odds. And yes because more birds are on one side than the other.