The perfect guide to the birds of the northeastern United States and eastern Canada, from the #1 birding website AllAboutBirds.org
All About Birds Northeast
Northern Cardinals: Habits, Habitat, History – Oakland County Blog
Northern Cardinal Overview, All About Birds, Cornell Lab of Ornithology
Northern Cardinal with possible eye disease and plumage abnormality - FeederWatch
Northern Cardinal Song
New Regional Bird Guides Simplify Identification
Backyard Birds of Eastern/Central North America: A Folding Pocket Guide to Common Backyard Birds (Wildlife and Nature Identification): The Cornell Lab of Ornithology, Waterford Press: 9781620052426: : Books
Songbirds: North Carolina's State Bird-How to Identify the Northern Cardinal - HubPages
Northern cardinal
Cardinal Rule: Female Birds Sing, Too - Scientific American
Bird, Cardinal