While carrying a Survivor you benefit from the following effects:

Decreases Wiggle effects, which cause you to strafe sideways, by 75 percent.
Increases Wiggle duration by 4/8/12 percent.

Crows startled by Survivors within 20/28/36 meters alert you with a Loud Noise Notification.
Spies from the Shadows has a cool-down of 5 seconds between alerts.

After hooking a Survivor, Pop Goes the Weasel activates for the next 35/40/45 seconds:

Performing the Damage Generator Action on a Generator instantly regresses it by -20 percent of its current Progression, after which normal Regression applies.

Increases your Field of View by 9/12/15 °.
Field of View gains do not stack