The Owl and The Bat

Two old friends an Owl and a Bat decided to have a night out, unfortunately, as we all know, Ole' Owl has poor eyesight, he can only see if the thing is already right in front of his face. Ironic though it may seem since his eyes are so big and bright that it's the only thing that you would see in the dark but I think the Creator forgot to fine tune his optical nerves or mebbe he ran out of 20/20 vision spare lens that what poor Ole' Owl must have was just a replacement or clone material. Anyway, to continue the story, Batty the Bat on the other hand have keen sense of hearing where the sound waves would vibrate when it hits a spot, cuz he got this vibra thing that he would launch when he flies around to keep him from bumping from anything cuz he's definitely blind. He got it from birth I think...So Ole' Owl and Batty Bat went on their adventure, Batty promised Ole' Owl here that he gonna warn him if there's something up ahead so he can avoid it in time and Ole' Owl promised Batty Bat to describe whatever he sees. So up ahead, they fly when suddenly Batty got his first hint of what's coming up ahead. So what do you think 'Ole Owl saw that stumped him into silence?