When the white pelicans show up in Florida they do not have the bump on their beak, it starts to grow in the spring and when it gets about 2 or 3 inches high, they leave here. I had always thought they stored water in it for the long flight home. I think it was last year that I found out it has something to do with mating. But now I wonder what role it plays. Do they have some sort of kinky sex with it? You rub my bump and I will rub yours. lol
Maybe they think those bumps are just super attractive! We have hundreds of them here on the river in Wisconsin for about a week, and then they move along, further north.
Maybe, I guess we will never know for sure. We only have them in the winter, we have the brown ones that stay all year.