Alabama's yellow cardinal: The science behind an amazing, rare bird
Can A Cardinal Be Half Male Half Female? Birds Advice
A cardinal that is half male, half female puzzles scientists, delights birdwatchers
Pennsylvania man captures photo of rare half-male, half-female cardinal – KIRO 7 News Seattle
Once-in-a-lifetime, half-male, half-female cardinal photographed in Pennsylvania
Birdwatchers photograph rare 'half-male, half-female' cardinal in Pennsylvania
Half Hours with Modern Scientists, by Various—A Project Gutenberg eBook
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What did the ancient Maya see in the stars? Their descendants team up with scientists to find out, Science