Originally Posted by NeatNit
Even though this isn't mentioned in the puzzle (there has been enough talk about that), you cannot have a bird carrying less than its max capacity, unless it's not carrying anything.
That's not good puzzle design at all! If the solution isn't marked as correct unless you obey said condition, then the condition should be mentioned in the effing puzzle!
One possible idea might have been to say "use as few birds as possible", just like in the Bugs in Boxes puzzles where you have to use as few boxes as possible (which I came to like, by the way, once I realized that "each green bug needs three spaces" means that each rectangle containing green bugs has an area of 3*[bugs] spaces, and not just 3 spaces). I dunno -- anything but keeping the rule a secret and giving the solver no reason to suspect it's even there!
Puzzle design like this makes me sad.