What name is given to ducks which feed mainly at the surface rather than by diving?
Diving duck several of the most familiar Northern Hemisphere ducks. This group of ducks is so named because its members feed mainly by diving, although in fact the "Netta" species are reluctant to dive, and feed more like dabbling ducks. These are gregarious ducks, mainly found on fresh water or on estuaries, though the greater scaup becomes marine during the northern winter. They are strong fliers; their broad, blunt-tipped wings require faster wing-beats than those of many ducks and they take off with some difficulty. Northern species tend to be migratory; southern species do not migrate though the hardhead travels long distances
Surface-supplied diving than a scuba diver as there are normally two alternative air sources available. Surface-supplied diving equipment usually includes communication capability with the surface, which adds to the safety and efficiency of the working diver. Surface-supplied equipment is required under the US Navy operational guidance for diving in harsh contaminated environments which was drawn up by the Navy Experimental Diving Unit. Surface-supplied diving equipment is required for a large proportion of the commercial diving operations conducted in many countries, either by direct legislation, or by authorised codes of practice, as in the case of IMCA operations. Lightweight demand helmets are rigid