Following current, tendency to lose a wader (4)
I believe the answer is:
ibis
'wader' is the definition.
(I know that ibis is a type of wader)
'following current tendency to lose a' is the wordplay.
'following current' becomes 'i' (symbol for electric current. I am not sure about the 'following' bit.).
'tendency' becomes 'bias' (bias is a kind of tendency).
'to lose' indicates named letters should be taken away.
'bias' with 'a' removed is 'bis'.
'i'+'bis'='IBIS'
(Other definitions for ibis that I've seen before include "Revered bird" , "Bird sacred in Ancient Egypt" , "Winger" , "Eastern" , "Retreat" .)