It's just possible that a certain low-down coyote left his sign there.
6 seconds sound clip from the The Big Trail (1930) movie soundboard.
You can hear this line at 00:17:40 in the Blu-ray version of the movie.
Quote context
[...]
- And they've left their mark.
- Say, who was that he-grizzly that just went by?
- You reckon you'll ever find out who downed old Ben?
- It's just possible that a certain low-down coyote left his sign there.
- I've changed my mind. I'll scout for that bull train after all.
- Well, that's a ray of sunshine. Shake hands afore you change your mind again.
- Got a good wagon boss for the trip?
[...]