Cardinals have been gloriously prevalent in our backyard this Spring!
Here is the female partner of our fabulous pair gathering nesting twigs for her work along the Maumee River bank. She takes on most of the nest-building duties. She is more careful to stay hidden, using her camouflaging feathers.
Although the beautifully red male does contribute a few items to the nest now and then and visit the female to check her progress and offer encouragement, his main objective is to guard the operations. And he makes no bones about his presence, standing tall and alert and visible. From his heights, he continuously watches over his female partner and whistles and signals to her whatever messages are necessary.
(See http://www.horsesandanimalsaretalkin.wordpress.com for more.)