This spring I have been listening to the Cardinals singing in our neighborhood here in Central Illinois, and I came to the conclusion that they had at least three different songs, but I had no idea what the songs ment. I just assumed that they were all some kind of mating call from the males, since I could not get close to all of the singing Cardinals to distinguish gender, again I assumed they were all males. However, I wondered why the male would have three different mating calls. Then I found this article that said that females also sing. So some of the songs I've been hearing, are female songs.
I also learned that once they pair up, the male begins to brings food to the female, and feeds her beak to beak. I thought, that is so sweet and loving. I learned that he would even sit on the eggs part of the time just to give her a break.

We humans could learn a lot from these beautiful birds.
He who has eyes, let him see!
He who has ears, let him hear!

For more information on the "Songs Of The Cardinals"