The posture of a loon is very indicative about how it is feeling. Visual displays can be very informative to the observer who can understand their meaning and respond appropriately. Most loon behaviors are related to basic survival skills, such as feeding, mating, territorial defense, and protection of their chicks. 

Hiding position: The loon is riding very low (almost flat) on the water. This position, often used by juveniles when they feel threatened, provides camouflage from predators, and the bird is able to quickly dive to get away from a threat.

Peering: Loons "peer" underwater to look for prey or to see what other loons are doing. Chicks will also peer to watch their parents catch fish.

Head high with "worried brow": This position means that the loon is alert, and slightly concerned by a possible threat, such as a predator, another loon, or human/boat.

Penguin dance: This is an aggressive display, usually done by the male, to defend its territory or chicks from another loon invading its territory, a predator, or a boat (both motorboats or ones that are paddled) with people aboard. This display is extremely energy intensive, and the bird may do it repeatedly until the perceived threat moves away. Two males will penguin dance at each other when they are fighting over a territory.

Splash diving: A loon will quickly “splash dive” when it is feels threatened – this is a very fast dive that is accompanied by a splash as the loon enters the water. The bird often squawks or yelps as it dives. If you see a loon splash diving, it is probably upset about something and is trying to get away.

Wing rowing: Wing rowing is most often observed when two loons are fighting, and one is trying to get away from the other bird. The loon losing the fight moves rapidly across the water, propelled by its wings “rowing” through the water. During a fight, there are also usually loud tremolos and yodels, and a lot of splashing, creating quite a commotion as the birds chase each other back and forth across the lake. Occasionally, a bird will wing row just to move quickly to a different part of the lake. In these instances, you would only observe one loon wing rowing, and there probably wouldn’t be any calling.