In this context it probably is just ground up pellets. There are three definitions to mash as far as I could find:
- Harrison's company makes a specific product called "mash" which is either the pellet ingredients before they are pressed into pellets, or, ground up pellets (unknown based on description, and seems to vary batch to batch but this is what my dude eats)
- ground up pellets
- breakfast cereal for birds ("mash" from various cereals/grains like oatmeal and/or oat groats, wheat berries, corn kernels, brown rice, buckwheat, millet, amaranth, etc)
Sprinkling a little water helps the powder/bits stick to seeds. An alternate is to use a bit more water that makes a paste, mix seeds into it, then for sure the bird will need to rummage. My dude did not like when I did this, he was not a fan of wet seeds and would just go on hunger strike. This changed later on when we introduced the pumpkin puree, and he didn't seem to mind once he learned how to "forage" (although, I use this term loosely he's still not very adept at it, but getting better).
Here are a few other methods to consider with the powdered pellets:
- mix the pellets (better to grind them up, but not necessary) with a little apple or fruit juice (not for long term due to sugar)
- mix the ground up pellets with a vege puree like pumpkin or butternut squash (just enough to get things sticky, does not take much at all, and you can see my thread here on the topic)
- make cookies/birdie bread from the ground up pellets
In these three methods, do try mixing some seeds into it, and gradually reduce the seeds. This video is one of the better ones showing how to create a mixture with declining seed amounts:
You can use any kind of pellet powder you wish, doesn't have to be harrison's like in the video. I use 1 cup pellet powder, one metric plop of puree (1/8-1/4 cup?), one egg, and a tsp of baking powder (unless using a birdie bread mix). I use a small disher to make little balls, which I bake and freeze - my guy would not be able to consume even a small-cupcake-tin sized treat before it goes bad.
The cookie/bread method likely words best if you can get the bird on a flat surface to chomp into the cookie and break it up, then (s)he'll peck at the bits like a chicken. Theory here is, once they are doing that, you can spread a little whole pellet around the crumbs and they'll peck at it and eventually learn to eat.
There are many other methods, too.. it takes patience.
PS: If you don't feel like making your own puree, and are in the usa, this brand has organic canned stuff that my guy really likes:
Whole Foods o365 brand also works if they are organic.