The most common and most likely answer to this crossword clue is the 9 letter word GUILLEMOT
I've seen this crossword clue in The Daily Telegraph
G
U
I
L
L
E
M
O
T
More clues leading to the result GUILLEMOT
- Diver in vehicle test on craft circling lake
- Craft crossing loch on annual check finds diver
- Bird from lake caught by cunning cat turning
- With seabird circling, I get book to look up ‘auk’
- Diver’s test on craft round loch
- Bird exhibited by student entering art examination
- Emu got ill, sickly bird
- Bird round island in my view recalled as a diver
- Diver‘s shame, eating most of fruit
- Bird taking most of fruit — shame about that
Buddy explains!

The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GUILLEMOT mean?
GUILLEMOT noun- Any seabird belonging to the genera Uria and Cepphus of the auk family Alcidae. They have black and white bodies and are good at swimming and diving.