Which kind of flowers (I would only like to limit it down to 2) do Goldfinches, Cardinals, and Oriels seem to be attracted to?
Goldfinch pick seed from seedheads of coneflower and black-eyed susan. They also eat seed from many weeds like thistle.
Cardinals eat many kinds of tree/shrub berries and insects.
Orioles spend the winter in S. America. When they return to the north they eat insects and some fruits.
If you have room for trees, I would add that I have seen Orioles feeding on blooms of both Buckeye and Catalpa trees. I've read that they will feed on nectar of certain annual/perennial flowers, but i've never witnessed that. They seem to stay higher up in trees after they return in the spring.
Don't Cardinals like Holly??
I put out black oil sunflower seeds to feed the birds. The feeders attract a lot of goldfinches, purple finches, bluebirds and sometimes Cardinals (rare). For a VERY SHORT period in spring I see Orioles on the feeders. But I am in Northern Alabama so the Orioles do not stay here long.You can attract Orioles to your yard in the southeast north of Florida by putting nesting materials in your yard..Orioles use hair, fishing line, string, and yarn in addition to some natural materials to build their nests.
Also adding halved oranges to your feeder areas will attract Orioles. They will come to a hummingbird feeder or you can get a special Oriole nectar feeder. (not sure where Oriole nectar feeders are sold)
Adding cracked corn to your feeders will attract cardinals if you have dense shrubery or bushes in your yard. Cardinals like bushes..Adding some holly bushes to your yard will attract Cardinals for you.
I'll never forget the blueberry plant I put in a few years ago.....one Spring I was watching them slowly grow larger and riper.....waiting for the perfect day to pick them for some nice blueberry pancakes....(still a rather small bush) and one fine spring morning I went out.....and all the bluberries were...GONE!
And there on the pitch of my roof was a beautiful Mr. Cardinal with a nice plump belly singing the smuggest little song. "I just had your wonderful blueberries" I think it went. How could I mind? I went to the grocery store and bought a pint for me. And yes, goldfinces love thistle and coneflowers.
We have some of all.I put out black oil sunflower seeds and thistle.Can't keep the sunflower seeds.