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
Remigius	-	Late Roman
Val	[væl]
Doroteja	-	Slovene, Croatian, Serbian, Macedonian
Nechemyah	-	Biblical Hebrew
Friedman	['fri:dmən]
ReİS	-	Turkish