be (one's) pigeon

To be one's area of expertise or responsibility. Primarily heard in UK, Australia. I can't approve expense reports, but Betty can—that's her pigeon.

Name	Pronounced	Usage
Mostyn	-	Welsh
Anne	[æn]
Hye	hye	Korean
Ahura Mazda	ə-HUWR-ə MAZ-də (English)	Persian Mythology
Balderstone	['bɔ:ldəstəun]
NurettİN	-	Turkish