Not a 'real' yellow cardinal [see the second link] but a Northern or Virginia cardinal that came out yellow instead of red. And look at the third link for an even more unusual Northern cardinal.
Yellow Northern Cardinal
http://www.audubon.org/news/why-norther ... ent=medium
True Yellow Cardinal {these birds are in my country of birth]
https://neotropical.birds.cornell.edu/S ... 1/overview
A Northern cardinal half male and half female!
http://www.chicagotribune.com/news/loca ... story.html