A cardinal that is half male, half female puzzles scientists

Rare half-male, half-female cardinal spotted in Pennsylvania

Puzzles For Him Nautilus Puzzles - Wooden Jigsaw Puzzles

Why Is This Northern Cardinal Yellow?

Rare half-male, half-female cardinal spotted in Pennsylvania

Can A Cardinal Be Half Male Half Female? Birds Advice

Science Roundup: From a bird that is half male and half female to asymmetric dancing lights, The Independent

Rare cardinal sighting renews interest in work by local researchers

Deep-Sea Jelly Reignites Debate on Remote Species Identification

Dr Con Man: the rise and fall of a celebrity scientist who fooled almost everyone, Science

Bird Trivia: Funny, Strange and Incredible Facts about North American Birds: Tekiela, Stan: 9781591938101: : Books

California Condors Are Capable of 'Virgin Birth' - The Atlantic

Urban Bird Feeders Are Changing the Course of Evolution - The Atlantic