Badgers I hunt to reduce numbers (4,3)
I believe the answer is:
thin out
'reduce numbers' is the definition.
'thin out' can be an answer for 'reduce' (thinning out is a kind of reducing). I'm not certain of the 'numbers' bit.
'badgers i hunt to' is the wordplay.
'badgers' indicates anagramming the letters (I've seen 'badger' mean this (the letters must be badgered or bothered)).
'i'+'hunt'+'to'='ihuntto'
'ihuntto' anagrammed gives 'THIN OUT'.
Can you help me to learn more?
(Another definition for thin out that I've seen is " Become sparser".)