The type of bird seed you choose for your feeder will be responsible for the number and types of birds you'll attract to your bird feeder. Different types of birds, just like humans, have their preferences when it comes to bird seed. It's very hard to please all birds with one kind of bird seed. Black oil sunflower seeds are one of the most popular types of bird seed amongst a number of different species of birds. An inexpensive bird seed option is called 'bargain mix' which is made up of a variety of different seeds, buckwheat and rice. Bargain mix may often involve more cleanup, as some of the birds will pick through the bird feed, take what they want and leave what they don't. Bird field guide books and bird feeding resources can be found online to help you decide which type of seed will attract your favorite species of bird to your bird feeder.