Strange Gunk on My Red Belly's Head?

Last night we went out for dinner and left Mango in his cage. We played with him all day, but this would be the first time we have left him alone for the evening. He is often home alone during the week while Im in lab or Dave has class. Our schedules are pretty random, and he has only been with us a few weeks so I doubt he has a concept of when we should or should not be home. I double checked that everything was secure, we left the radio on for him and there was nothing he could have pulled into his cage. When we got home he had some strange gunk on his head. It looked like he had something on his foot and then scratched his head. The first think I did was check his nostrils, but they are dry and clear. There was nothing on his feet either, and his behavior hasnt changed at all. The only this we did different yesterday was give him a raspberry. He ate about half of it around noon. He made a big mess of his face and feet, but it was a white goo on his head and it had dried up hard. Im still trying to rub it out of his feathers, hes not a huge fan of having his head touched. If hes ichy he lets me scritch but he keeps threatening to bite and gets all offended for no reason. Anyways, I dont know what this could have been? Could he have regurgitated and got it on himself. I clean his cage twice a day, and there was nothing in there that looked like it could be the goo. Has anyone had this experience?

My only guess would be bird poop.

It didnt look like poop, and hes usually pretty clean (not his space but his feathers). So weird, its crusty and shiny. Dave thinks it was drool, but do birds actually produce a significant amount of saliva?

Remember the hotel scene from the movie "There's Something About Mary". That was not hair gel.

If your bird is mature it is highly likely he has regurgated on his foot & maybe scratched his head.

Or he could have vomited. Check his cage to see if there is any bits of stuff stuck to the sides of the cage.

Usually when a bird vomits they flick it all over the place & that's is usually how it gets on their head.

He is only 7 months, I have never seen him display any sexual behavior, I suspect he vomited. I cant find any traces of it anywhere, but we will keep an eye on him.