Engaged in competition with bird and tailless parasite (7)
I believe the answer is:
emulous
'engaged in competition' is the definition.
'emulous' can be an answer for 'competition' (I've seen this before). I'm not certain of the 'engaged in' bit.
'bird and tailless parasite' is the wordplay.
'bird' becomes 'emu' (emu is a kind of bird).
'and' says to put letters next to each other.
'tailless' means to remove the last letter (the tail of the word is removed).
'parasite' becomes 'louse' (I've seen this before).
'louse' with its last letter taken away is 'lous'.
'emu'+'lous'='EMULOUS'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for emulous that I've seen before include "Eager to equal another's deeds" , "competition" , "Seeking to imitate" , "Feeling rivalry" .)