Like blue jays, cardinals are mad for peanuts. They prefer both peanuts and safflower to sunflower seeds. When I moved to my home, we had no cardinals. Now, we have about 10 pair. They and the blue jays flock together in winter. One blue jay keeps watch in a tree near my property and as soon as it sees me come out to the feeder, it sounds the alarm and all the jays and cardinals come flying in, along with chickadees, tufted titmice, nuthatches, woodpeckers, white throated sparrows and the odd non-migrated blackbird.
Cardinals love tangled bushes and hedges for their nests. They also eat the tiny pears in my pear tree in late autumn, early winter. I sometimes feel I like winter better than spring and summer, because spring and summer bring domineering redwing blackbirds and grackles. I don't see the smaller birds like the chickadees again until winter. And the continuous sound of RWBB and gravels is unpretty.
Thanks for the interesting information about cardinals. You are obviously an experienced bird watcher! I agree, winter is a wonderful time to observe birds at feeders. In the spring, Mr. Redwing and his harem of females chase the other birds away and devour all the food at our feeder. One spring they nested very close our back door, and they even chased me out of the yard for several weeks!