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
Dawn	[dɔ:n]
Ambrosine	am-BRO-zeen	English (Rare)
Primitiva	pree-mee-TEE-vah (Spanish)	Spanish, Late Roman
Yamanu	-	Egyptian Mythology
Aingeru	-	Basque
Eva	['i:və]