Merritt Island Florida, Jan 22, 2015.
Unusual looking birds.
The remarkable bill of the Black Skimmer sets it apart from all other American birds. The large red and black bill is knife-thin and the lower mandible is longer than the upper. The bird drags the lower bill through the water as it flies along, hoping to catch small fish.
At hatching, the two mandibles of a young Black Skimmer are equal in length, but by fledging at four weeks, the lower mandible is already nearly 1 cm longer than the upper.
source - https://www.allaboutbirds.org/guide/Black_Skimmer/