The most common and most likely answer to this crossword clue is the 10 letter word EARTHWORMS
E
A
R
T
H
W
O
R
M
S
More clues leading to the result EARTHWORMS
Buddy explains!

The straight part
We know that "food for some birds" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case food for some birds = earthworms.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 EARTHWORMS mean?
EARTHWORMS noun- A worm that lives in the ground.
- A worm of the family Lumbricidae, or, more generally, of the suborder Lumbricina.
- A contemptible person; a groveller.