A leggy bird (5)
I believe the answer is:
stilt
'bird' is the definition.
(stilt is a kind of bird)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for stilt that I've seen before include "Wading bird; post" , "Aid for walking tall" , "Long-legged wader" , "Walking pole; wader" , "Long-legged bird" .)