Guys, guys, guys...
They weren't birds...They were aliens.
They travel in threes in case one is attacked the other two can plant their photon blaster ray on ya.
Sorry...I had to.
A318, A320, A332, A333, B1900, B722, B732, B733, B734, B735, B737, B738, B772, CR1, CR2, CR7, CR9, MD80, MD81, MD82, MD8