A question about ergative markers

[William McGregor]

Dear typologists,

I am wondering if anyone knows of any language with more than one ergative
marker?

Obviously I'm not thinking of more than one allomorph, but where there are
two morphemes both marking ergative, but with some nuance. For instance,
Warrwa has -na @ -ni and -ma. It seems that the first is an ordinary
ergative marker, while the second is a focal ergative marker, marking
unexpected agents.

If anyone is aware of anything like this in any other languages I'd
appreciate hearing about it.

Thanks,

Bill McGregor