Spotter

noun

1. A person who observes something.
2. A member of a sniper team who in addition to this function is responsible for providing additional information about targets from a different point of view.
3. One who supervises a person performing an activity, in order to help them should they be unable to complete it.
4. A person who gives directions of a crane or vehicle challenging to navigate from a different point of view to the moved load.
5. Dolphins of the genus Stenella, and specifically Stenella attenuata distinguished from the streaker (Stenella coeruleoalba) and the spinner (Stenella longirostris).