The birds like sunflower seeds the best, but so do the squirrels.
On the advice of my brother I switched to safflower seeds. The squirrels won't eat those. But I found that I lost the goldfinches, junkos, woodpeckers, and chickadees, amoungst others. And safflower seed is usually around $1 a pound minimum IF you buy a 50 lb bag. So in later years I was often taking down the feeders once summer started.
This spring I put the feeders up and let the squirrels eat their fill of sunflower seeds because I noticed that they were eating the budding leaves on my shag bark hickory tree. Once I switched to safflower seeds I once again lost the majority of visitors to my feeders.
So I decided to look into "squirrel proof" bird feeders. There are some good ideas out there, but they are all so expensive! And the tree rats are often able to defeat the "squirrel proofing" by hanging off the side and scooping out the seeds.
I found an all steel type that closes access to the seed if a squirrel puts its weight onto the metal perch. It has mixed reviews. But it is far cheaper than some other brands that use plastics or acrylics for the body of the feeder.
http://www.urbannaturestore.ca/squirrel ... uctReviews
There's also a red feeder of the same design, but it seems the green one does a bit better job. If you read the reviews on both colour models, you'll see that these things can be beaten by the smarter tree rats. But I bought two green ones anyway. The trick is to keep the furry thieves off of the feeder in the first place:
http://www.urbannaturestore.ca/18-quot- ... el-baffle/
According to the reviews, this is the one to buy. I saw the baffle defeat it's first squirrel within 20 minutes of finishing the installation and the filling of the feeders.

Some reviews said that the birds didn't take to the new metal feeder straight away or at all. So I have hung one of my old plastic feeders on the other hook. It also acts as a counter balance, since the metal feeder holds a lot of seed and is rather heavy. Hopefully the old feeder will lure in the birds, and then they'll try out the new feeders too.
