Ruby Tuesday - Father Cardinal

I have a pair of Northern Cardinals which have nested nearby, although I have not seen their nest. The male is a bright red while the female is more of a rust color.  They enjoy my sunflower seeds.   I believe the female is sitting on eggs because I have not seen much of her lately.  Instead, the male picks up seeds from the feeder and flies off to feed them to his mate.  Cardinals are pretty birds and make a very distinctive call, whoit, whoit, whoit, whit-cheer, whit-cheer.  At least that is what it sounds like to me.