`Ornithology: The Z-Penguin' 

Abstract: The Z-Penguin is a flavour-changing neutral current
generated through the electroweak interactions of the standard
model. It is highly sensitive to new sources of flavour violation. In
this talk I will discuss the standard model prediction and new physics
sensitivity of observables generated by the Z-Penguin. I will
concentrate on the currently measured B_s -> mu^+ mu^- decay mode and
on K -> pi nu nu-bar mode, which will be measured in the near future.