Barking Up the Wrong Tree

I've heard the expression all my life, know what it means and where it came from but had never actually seen it until today.  Tanya let the dogs out for a run.  They headed to the marsh for some hunting and flushed a big yellow tomcat, likely a distant relative of Kuchma.  The cat made a run for it across Lucia's garden patch and up one of our three big walnut trees.  The dogs were very excited and pleased with themselves, jumping and barking around the tree.  Then we noticed Volk jumping and barking at the tree beside it.  No cat up that tree.  We looked.  Seems he had forgotten up which tree he chased the cat.  Dumb as a hammer, that boy.