Flier showing part of menu that changes (8)
I believe the answer is:
nuthatch
'flier' is the definition.
(nuthatch is a kind of birdanimal)
'part of menu that changes' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'NUTHATCH' can be found hidden inside 'menu that changes'.
'showing' acts as a link.
(Other definitions for nuthatch that I've seen before include "Trunk-climbing bird" , "Songbird feeding on insects and kernels" , "Singer" , "Small songbird often seen on tree trunks" , "Songbird named from its penchant for a kind of fruit" .)