Let the children observe the birds as they come to feed. Graph how many birds come each day. Compare the numbers to see if there is a growing number. Make sure you check the seed daily or the birds will not come to depend on that food source. Lots of times, some birds will get only the kind of seeds they like and leave the rest.
Some birds leave the hulls.
So be sure to change or add to the feed about every other day. After attracting the birds, determine the different types of birds that come to feed. Name the birds. They don't have to be the real names, let the kids come up with a name, just like scientists do. Make another graph to count the different types of birds that come to the feeder.