Do birds smell?

My last blogpost about the Crimson rosella and how it can smell its own subspecies and gender inspired me to have a closer look at the bird sense smell.
I was already reading Birkhead's book 'Bird sense' chapter 'seeing' and the chapter 'smell' gives also a detailed history on bird smell research.
This week I will post daily on my social network Birdbehaviour about birds and their sense to smell. You can follow this on Twitter or Facebook by #BirdSenseSmell.
As always, your thoughts and feedback on this are very welcome.
I hope to see you online.