Pyrrhuloxia (Cardinalis sinuatus ) - Photos, range, physical traits, and natural history. - http://animaldiversity.ummz.umich.edu/site/accounts/information/Cardinalis_sinuatus.html
Cardinalis cardinalis (Northern Cardinal) - Scientific classification, range, physical traits, and natural history. - http://animaldiversity.ummz.umich.edu/site/accounts/information/Cardinalis_cardinalis.html
Northern Cardinal (Cardinalis cardinalis) - Photo, range maps, and facts about this bird's diet and habitat. Includes a sound file. - http://www.nenature.com/NorthernCardinal.htm
Pyrrhuloxia (Cardinalis sinuatus) - Photo of this species, also known as the Gray Cardinal. - http://www.nps.gov/whsa/bird%20list/pyrrhuloxia.htm