His nose is 6+ feet up in the air. He doesn't run his nose past vegetation at shall we say 'scent marker height', like other 4-legged animals do for their species.
He would need to be picking at the right blueberry bush at the right time? over possibly a very large area.
These creatures could just be incredibly sensitive to a potential mate's scent (in the air), but there seems to be so few out there it seems like a crap shoot with unusually bad odds to me.
I am not sure on the sensitivity of primates or apes, but bloodhounds, under optimal conditions can detect a single cell or two with their nose. The olfactory sensitivity is directly related to the number of olfactory receptor cells.
Animals that use scent place the scent where they can easily detect it, and how tall are trees usually?