PELICAN PROBLEM PROBED

These two photographs were taken some years ago (just before Corinna and I got married) at Farnham Birdworld, and show what I think are white pelicans (Pelecanus onocrotalus) but could be American white pelicans (Pelecanus erythrorhynchos) I cannot remember which.

My query, in fact the whole reason for posting these pictures does not actually have anything to do with what species they are, but actually concerns the weird bulgy things above their beaks on what their foreheads would be if I was going to be ridiculously anthropomorphic which I'm not. What they hell are they? Ironically I took photographs of these particular birds because the bulgy bits were lease prominent and at the time I was looking for stock pictures for the CFZ photo library, rather than for pictures of weirdness for the ongoing teratology discussions here on the bloggo.

I have no idea where to start looking for information on the subject, and thought that in the best traditions of Esther Rantzen (whom, I met once, and who was a charming woman) that I would throw the question open to you guys and girls in the bloggo readership.