Set a heavy saucepan on a kitchen scale and set to zero grams. Add the sugar to the pan; re-set to zero. Add the corn syrup. Stir well; Over medium-low heat, cook the sugar mixture and stir often until bubbling and thickened.

Set the bowl of the food processor on a kitchen scale; set weight to zero. Add the lard; re-set the scale to zero. Add the peanut butter; re-set the scale to zero. Add the cornmeal. Process in the food processor until the mixture is smooth and well-blended.

Set the bowl of the food processor on the kitchen scale. Add the rolled oats. Process until the mixture is well-mixed.

Set the bowl of the food processor on the kitchen scale. Add the birdseed or other nuts. Process until the mixture is fairly smooth and the nuts are ground relatively smooth.

When the sugar syrup is hot and bubbling, add it quickly to the mixture in the food processor and blend until well-mixed. You may have to scrape and push it around several times.

Wearing latex gloves, push handfuls of the seed mixture into the water bottles. Keep filling and pushing it down to fill all the gaps.