Why do pelicans suck in water while taking in fish?

Pelicans use their unique throat pouches to efficiently scoop up water and fish simultaneously while diving or skimming the surface. When they open their bills, the pouch expands, allowing them to trap both water and prey. After capturing the fish, they then drain the excess water by tilting their heads back, effectively retaining the fish for swallowing. This feeding technique allows them to maximize their catch in a single motion.