Answer:
the author's implicit message in this statement"I finally heard the voice of Merlin thanks to a surprising source: the haunting, mysterious hooting of a great horned owl outside the window of my Colorado home." Is:
The author realized Merlin's voice should have the same qualities as the owl's voice.
Step-by-step explanation:
First of all in this answer the author is clearly making use of his imagination to say that Merlin's voice should have been similar to the owl. Therefore we have only two options. The first says that Merlin's voice should have the same qualities o the owl's voice. The author here is wishing instead of knowing the voice. The second option says that Merlin's voice should seem like it is hooting as the author actually knew Merlin's voice. While it is a fictional character as he states.