We have a large magnolia tree in our back yard and a little red squirrel is enlarging a crack in the tree. We are afraid that the tree will die. He has made it almost big enough to get in to. Should we patch the hole? What is a good thing to patch it with? The tree is very near our bird feeders and very convenient for the squirrel to eat.
Thanks for your answer

Many years ago, I read that, the then common cement patches, were a bad idea because they drew damp, causing rot. The book suggested mixing tar and rock. You can buy asphalt patching compound premixed. I have also used roof cement. Likely neither is attractive to squirrels or ants.