Which bird is the fastest swimmer?
In
flight, the fastest bird is the spine-tailed swift of Siberia which can
reach speeds in excess of 100 miles per hour, but the fastest bird in
the water is the Gentoo penguin, which swims at about 22 mph. (Watch
this video of a Gentoo swimming madly to avoid a pod of hungry orcas.)
Source : http://blog.nwf.org/2011/03/the-fascinating-things-about-creatures-that-swim