Everyone else has offered some good advise for you. I have a few tips I'd like to add about my backyard birding photography.
Move slow, that is when I am outside, I see a bird, I stop dead, then if the bird stays on the branch or on the ground I inch slowly toward them. I've gotten within five feet of cardinals, and bluejays (what I have here).
Also something I've learned about birding, don't wear bright colors in your clothes, I wear blue jeans, and blue or gray shirts.
Don't wear smelly perfume, or men's cologne. Don't smoke, if you're a smoker.
After hanging feeders, also make sure you have source of water, I have a homemade birdbath situated just under the and off a bit from the feeders.
Btw, I shoot handheld, no tripod.
I was two feet away from this BlueJay when I shot it.