Cardinals, due to their colors and shapes, are arguably the favorite backyard birds of many of us. Yesterday was a cold and very windy day with a bit of snow, which may explain why we had so many of them come to our bird feeder. At one time I counted as many as seven, both males and females, and there could have been others unseen as they gleaned sunflower seeds that had fallen to the ground.
Normally, if a male Cardinal is at the feeder, the females keep a respectful distance, waiting until he leaves. He is only deterred by the Red-bellied Woodpecker which is slightly larger.
On the other hand, female cardinals are not averse to fighting others of their kind for a seat.