What does the cryptic crossword clue "Bird breeds with rat, remarkably (9)" mean?

The definition is "Bird". The wordplay uses an anagram. anagram of BREEDS + RAT, = REDBREAST; definition: "Bird" The answer is Redbreast.

Bird breeds with rat, remarkably (9)

Telegraph Prize Cryptic #3050 | 14 Down | 2020-04-05 flower