Mythical female means to catch bird with speed (5,5)
I believe the answer is:
water nymph
'mythical female' is the definition.
(female spirit in Greek myth)
'means to catch bird with speed' is the wordplay.
'means' becomes 'way' (a way or means of doing something).
'to catch' indicates putting letters inside.
'bird with' becomes 'tern' (tern is a kind of bird. I am not sure about the 'with' bit.).
'speed' becomes 'mph' (miles per hour).
'way' placed around 'tern' is 'waterny'.
'waterny'+'mph'='WATER-NYMPH'
Can you help me to learn more?
(Another definition for water nymph that I've seen is " Naiad".)