My young child is now infatuated with birds (watching them). She watches them at my parents. We don't have bird feeders up but we are planning on it. I rarely notice birds around here in the winter and honestly I'm clueless when it comes to birds. I'm going to put out suet feeders today (my daughter and I are doing this). How do birds know that we are trying to feed them? How long will it take to train them so that they will come?