Blackbirds and slugs

Guys
I've been enjoying watching my local blackbirds. I couldn't make out, at first, what they were doing. It appears that they have learned how to feast on big fat slugs, the Spanish slug, etc, which exude lots of slime. They keep wiping them through the grass or compost to get rid of it then, by-by slug.
Apparently, one of the few species that have discovered this trick and is now well documented.
One learns something new every day.

 

I've only seen crows do this.
Often they do it and decide not to eat it after all, and who can blame them.

 

I've not seen it but I very rarely see a slug in my garden.

 

The black birds here do it all the time even if they eat suet pellets i've even seen them with nowt in they're beck's and wipe the grass