It can also fly on coal! (3)
I believe the answer is:
tit
'fly on coal' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Maybe there's an association between them I don't understand?
'it can' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'can' becomes 'it' (I can't justify this - if you can you should give a lot more credence to this answer).
't'+'it'='TIT'
'also' is the link.
Can you help me to learn more?
(Other definitions for tit that I've seen before include "Boob made backing" , "Small bird that lives off insects" , "What you swap for tat" , "Small songbird" , "18's [BIRD]" .)