I believe it, I think their noses are much finer than their ability to process all the scents.

If they learn to recognize a certain scent above all the other scents, their noses can be unbelievable.

I had a Weimaranar that was from a line renowned for their noses. He was born hating Fox. He could scent a Fox from a long way off.

He was napping in the back of my Jeep as I was glassing a field with a lot of Deer traffic. He popped to his legs, stuck his nose out the window, made his WTF noise and pointed. That Fox was along ways off.