Some of my female budgies do the same thing- toss the seed and other food out and onto the floor of the cage. Females do this much more often than males. It's very frustrating because it's very common and very normal but very wasteful. I gave my girls a tube dispenser for seed to make it harder to toss it but I also feed them fresh cooked "chop" (a mixture of chopped vegetables and cooked grains) every day and I need to serve the chop in a dish. They love to eat the chop but half of it gets tossed on the floor no matter what I do. I also give them a large leaf of Romsine lettuce where day that they absolute love but they manage to shred and waste a lot of it.
I try not to let all the wasted food bother me. Birds are all messy eaters.
