What's with that back nipple?

[Jeffross1968]

We have no other name to call it, LOL! It's that nipple like thing, just above the tail on it's back. They like to nibble on it...very strange...

 

[Teach97]

oil gland for preening

 

[Jeffross1968]

Quote:
Really? How does it work?

 

[sourland]

They rub their beak on the oil gland picking up some of the oil and then groom their feathers. Thereby keeping themselves shiny and somewhat water repellent.