The most common and most likely answer to this crossword clue is the 7 letter word HERONRY
I've seen this crossword clue in Independent
H
E
R
O
N
R
Y
More clues leading to the result HERONRY
- Birds’ breeding-place identified by woman in train?
- Writer James gets run over in colony of birds
- Praise as before all round concerning colony of birds
- King once keeping rook along with old birds together
- Place for waders and half of rods possessed by scientist
- King including rook and duck in place for breeding birds
Buddy explains!

The straight part
We know that "birds together" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case birds together = heronry.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 HERONRY mean?
HERONRY noun- A breeding woodland for herons; a heron rookery.