The most common and most likely answer to this crossword clue is the 8 letter word SONGBIRD
I've seen this crossword clue in Financial Times
S
O
N
G
B
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R
D
More clues leading to the result SONGBIRD
Buddy explains!

The straight part
We know that "lark, perhaps" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lark, perhaps = songbird.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 SONGBIRD mean?
SONGBIRD noun- A bird having a melodious song or call.