Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
Full of useful information and chocked full of links to sites about feeders and books. Enjoyed looking through all the sites listed. You should like this as a guide to have on hand about how to attract certain species and how not to attract those you don't want. A few pictures but not for identifying species. Need a different book for that.