You know I love the birds. I buy black oil sunflower seeds in 50 lb bags and fill my bird feeder all year round. Instead of buying a filler or a special scoop, which do work, I made my own out of an old juice jug. The design is super simple, very effective, and free.
Just a utility knife to cut a decent sized hole in the top narrower side of the container (I used a cider jug, but you could probably use a half gallon milk jug, or some other similar plastic container). This hole allows you to use the container to scoop seeds out of your seed bag. Use the juice container’s pour hole to pour the seed/bird food into your bird feeder. Depending on your feeder, you might even be able to leave it hanging while you fill it, like I do.
The final step is to bask in the feeling of saving yourself $6-$15 and the glory of DIY!