Better Seed...More Birds...Less MESS and WASTE
"The seed that attracts the widest variety of birds, and so the mainstay for most backyard bird feeders, is sunflower. Other varieties of seed can help attract different types of birds to round out your backyard visitors. In general, mixtures that contain red millet, oats, and other “fillers” are not attractive to most birds and can lead to a lot of waste as the birds sort through the mix." - Cornell Lab of Ornithology
"Provide only high-quality birdseed and avoid bargain brands that list “filler” seeds as main ingredients (ex. milo, red millet, oats, rice and wheat). Not only will these seeds be discarded by wild birds, but they will also absorb moisture—promoting spoilage and fungal growth while attracting rodents and other species." - Nature Canada
Don't let the low price on a bag of birdseed mislead you into thinking you just got a good deal. Many stores (grocery, hardware, pet, big box, etc) will sell a bag of birdseed for a very low price. But as quoted above these bags are a bargain because the majority of the seed in the bag (on average 73% by weight) are fillers. Fillers are used to bulk up the weight of the bag to keep the bag at a price they believe the average consumer will purchase without too much thought.