The idea of investigating the relationship between birds and what type of seeds they eat is an interesting one. Years ago, I participated in a citizen science project of the Cornell Lab of Ornithology's seed preference study. The location of the feeder, type of feeder, time of day, what species of bird was attracted, type of seed, etc could all be investigated with the measure of how much seed was consumed as the dependent variable. The Corneyoull Lab may have some resources to get ur started on this, and they have a journal in which students can publishe there results. Local Audubon societies may be able to help with purchasing bird seed. Good luck! I'd love to hear about your study!