Wetlands can range from something as small as a pond to an ocean, and as little vegetation as a marsh to a swamps large trees. This causes these areas to have an extremely large variety of birds. A lake may have herons and ducks, but an ocean may only have gulls. Despite all of this the most common adaptation is to float on the water. This is commonly seen by swans geese and ducks, but it is such an important ability that even a heron chooses to float rather than stand in the water. While most do float there is still plenty of variation in how birds hunt in the area. Eagles are a very common site to find at wetlands because of the large number of fish at the top of the water.