The Eagle eye abilities is use for hunting and tracking, it will allow Arthur to see the path of the enemy. However, time won't slow down when using this abilities. To use this, you just press the L3 and R3 button.

How do I activate Eagle Eye?

When you activate eagle eye, you will be able to track your scent drifting towards the deer. Make sure to avoid the scent and move somewhat alongside but not directly towards the deer. L3 and R3 together to activate eagle eye.

How do you increase eagle eye in RDR2?

Eagle Eye is finite and will only last for around 10 seconds, before the player is forced out of it. The longevity of it can be upgraded with the Fox Claw Trinket, which extends the duration by 5 seconds.