Flocks of birds manage to navigate through difficult environments by individuals having predispositions to favor the left- or right-hand side. Researchers flew the budgerigars down a tunnel where they were met by an obstacle, and a choice of two paths to fly through. Sometimes the paths were of equal size, and sometimes one would be bigger than the other. Some birds had no bias and would choose the wider gap every time, while others with a distinct bias preferred going to one side, even if it was significantly narrower than the alternative.

Source: Birds display lateralization bias when selecting flight paths