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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 on an irregular basis in response to rainfall.
The evolution of flippers in penguins was at the expense of their flying capabilities, in spite of evolving from an auk-like ancestor that could 'fly' underwater as well in the air. Form constrains function, and the wings of diving flying species, such as the murre or cormorant have not developed into flippers.
The white-throated dipper and American dipper are also known in Britain and America, respectively, as the water ouzel (sometimes spelt "ousel") – ouzel originally meant the only distantly related but superficially similar Eurasian blackbird (Old English osle). Ouzel also survives as the name of a relative of the blackbird, the ring ouzel. [6]
[citation needed] Plunge-diving birds are notable for their beaks, necks, and morphing wings. Plunge-diving birds generally have a higher beak angle ratio than others. [ 5 ] Beak angle ratio is defined as the top angle divided by the side angle.
Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the same ways as other insects.Some diving insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete.
The American dipper's nest is a globe-shaped structure with a side entrance, close to water, on a rock ledge, river bank, behind a waterfall or under a bridge. The normal clutch is 2–4 white eggs, incubated solely by the female, which hatch after about 15–17 days, with another 20–25 days to fledging.
Diving equipment, or underwater diving equipment, is equipment used by underwater divers to make diving activities possible, easier, safer and/or more comfortable. This may be equipment primarily intended for this purpose, or equipment intended for other purposes which is found to be suitable for diving use.
In 1961 Donald Reid designed and built a single-seat craft (32.83 ft or 10 m length) capable of flight and underwater movement, the Reid Flying Submarine 1 (RFS-1 [4]). A 65 hp (48 kW) engine mounted on a pylon provided propulsion for flight; a 750 W (1 hp) electric motor in the tail provided underwater propulsion.