I was seeing many cardinals at my feeding area; now just 2; territorial ?

I have been putting out mixed seed, seed cakes & suet, this winter every day. I noticed about 5 or 6 cardinals with slightly differant colors and appearance. Lately, about the last few weeks, I am just seeing the same pair of cardinals every day and they usually come together. Do you think it is a territorial situation of fending off the others or what ?