I see bird over shipping hazard (7)
I believe the answer is:
iceberg
'shipping hazard' is the definition.
(I've seen this before)
'i see bird over' is the wordplay.
'see' becomes 'c' (the word for the letter, according to Chambers).
'bird' becomes 'grebe' (type of bird).
'over' says the letters should be written in reverse.
'grebe' back-to-front is 'eberg'.
'i'+'c'+'eberg'='ICEBERG'
(Other definitions for iceberg that I've seen before include "Four-fifths are under water" , "One sank the Titanic" , "threat to ship" , "Large block of frozen water" , "Variety of lettuce" .)