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
Bertram	BUR-trəm (English), BER-trahm (German)	English, German, Ancient Germanic
Aureliana	-	Italian, Ancient Roman
Miku	mee-koo	Japanese
Amadi (1)	-	Western African, Igbo
Mostyn	-	Welsh
Nicolina	nee-ko-LEE-nah	Italian