Geese at first found in eastern lake come into view (6)
I believe the answer is:
emerge
'come into view' is the definition.
(I've seen this before)
'geese at first found in eastern lake' is the wordplay.
'at first' indicates taking the first letters.
'found in' means one lot of letters goes inside another.
'eastern' becomes 'e'.
'lake' becomes 'mere' (mere is a kind of lake).
The first letter of 'geese' is 'g'.
'e'+'mere'='emere'
'g' placed within 'emere' is 'EMERGE'.
(Other definitions for emerge that I've seen before include "Come into existence" , "Materialize" , "Rise to notice" , "Come into view" , "Emanate" .)