Kind of finch the first of the swallows is related to (6)
I believe the answer is:
siskin
'kind of finch' is the definition.
'first of the swallows is related to' is the wordplay.
'first of' says to take the initial letters.
'related to' becomes 'kin' (I can't explain this - if you can you should believe this answer much more).
The initial letter of 'swallows' is 's'.
's'+'is'+'kin'='SISKIN'
'the' is the link.
Can you help me to learn more?
(Other definitions for siskin that I've seen before include "Singer" , "Yellow-green finch" , "Small yellow and black finch" , "Little bird" , "Greenish songbird of finch family" .)