Black skimmers have distinctive physical characteristics with respect to color and shape. The upper part of the body is black and the lower body and forehead are white. They have a bright red-orange bill with a black tip. The lower mandible is longer than the upper mandible by 1 to 2 inches. Black skimmers have a unique foraging behavior in which they fly low over the water while submerging their sharp, elongated lower mandible into the water. Once the prey comes into contact with the lower mandible, the upper mandible closes and the prey is captured. Their method of feeding allows them to be successful nighttime feeders. —animaldiversity.org

Common terns almost always reside in colonies. The colonies tend to be along ocean coasts, although they are also found on the shores of large lakes. Although all the terns migrate and live together, each family unit is responsible for its own feeding and care of eggs/chicks. They become very aggressive after their chicks learn to move on their own because of the likelihood that the chicks will be harmed or killed by predators. Both males and females bring food back to the nest, but males are usually more involved in feeding than females are.
animaldiversity.org
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