So unfortunately, this is an article that you will need to have a subscription to the Wall Street Journal. I believe you can also find it in the March 22, 2019 paper copy at your local library.
That said, the article is entitled “The Very Different Ways Cardinals and Blue Jays Get Their Hues” by Helen Czerski over at the Wall Street Journal. This article also takes me back the book I read a few years ago entitled Feathers : the evolution of a natural miracle by Thor Hanson. What a great book.
Sincerely-
Green Librarian
Green Librarian 