It was another challenge to feed birds, not squirrel at our back yard. We used different type of bird feeders at different locations of the back yard at very beginning.  Then, squirrels always had a way to get on the bird feeder and really enjoyed the food. We did not give up. This time we used a sheet-metal piece around at the top of the feeder hanger to fix the problem.  Not too bad.  So, squirrels then waited on the ground for leftover. The feeder is hanging from the gutter via a piece of wire and is far enough away from trees so squirrels cannot jump from tree to feeder.  Also the roof is a metal roof and is very hot during daytime.

Last bird feeder was made by metal net feeder hung by a small chain.  This is by far the best solution. The blue bird was Blue Jay and red bird was a Cardinal based on a ecologist.  The squirrel may be able to get onto the pole but has a problem with the chain and actually getting at the seed.  Now I might add that the squirrel should have sufficient acorns from the many oak trees we have in the yard.  Maybe they cannot remember where they buried them during the winter months.