When birds gather into groups, they fly in a variety of different formations and patterns.
Some birds fly in a formation that looks like the letter "V". Several species of geese, pelicans, and ibis are just a few of the more commonly known. This is their normal flying behavior, but can be more evident during migration due to the large numbers headed in the same direction.
Many of the other common birds fly in swarms or flocks without any obvious pattern. There's also a type of flock, exhibited breathtakingly by starlings, which is called a murmuration. It's a group of literally thousands of birds flying in magnificent and unique patterns.
I took the picture below over a lake in Rhode Island, United States, recently. The geese had just taken off and were flying in some side-by-side V-shaped groups. As they got farther away they gathered into smaller, tighter, individual V-shaped groups. Of course I've seen this behavior before, but on that particular evening, as I watched these geese leave the area, I began to ponder it more deeply.
Why do some birds fly in a V-formation? Is it just a random pattern or is there a reason for it?