Does any one know if the seeds of Himalayan Balsam are spread by mammals (or birds)?

Yesterday I was pulling some Balsam from an area that has been mostly eradicated of it over previous years. The only ones left are not the usual individuals but widely separated clumps comprising individuals of up to a dozen within a few inches square of ground.
I have never seen it grow like this and it looked as though a rodent may have stashed quantities of seed. It certainly made it easy to pull the lot in one go!

This may be a reason why Balsam suddenly appears in new places where there is non nearby.

I have googled this query and can find no reference to animals or birds eating the seeds. I can’t believe this doesn’t happen–but why has it not been recorded?