Birds with long tails! (5)
I believe the answer is:
kites
'birds with long tails' is the definition.
'kites' can be an answer for 'birds' (I've seen this before). I'm not sure about the 'with long tails' bit.
This is all the clue.
Can you help me to learn more?
(Other definitions for kites that I've seen before include "More than one toy" , "Aerial toys; birds" , "aircraft" , "Small hawks" , "They're flown in the wind at the end of a string" .)