waterwitch

Noun

water-witch (plural water-witches)

1. A grebe (Podicipedidae spp.)
   • ... bird was never seen again, dead or alive. There was a mystery about it , and when some one older and wiser than he told him it was a water witch or hell diver, the mystery was only half solved. Where did it go? How could it stay[…] Fortunately for the dabchick, […]1902, Florence Merriam Bailey, Handbook of Birds of the Western United States: Including the Great Plains, Great Basin, Pacific Slope, and Lower Rio Grande Valley, page 9
2. In particular, a pied-billed grebe (Podilymbus podiceps).
   • The Hell Diver seen was probably the Pied Bill Grebe, […] it surely is a water witch and has disappeared.1901, The Conservative, page 10
3. (UK, dialectal) A storm petrel.
   • Ten or fifteen dark little birds […] these are "Mother Carey's chickens," the "water-witches," Stormy Petrels, which are so familiar to the eye of the sailor, and the sight of which he dreads so much; […]1874, Alfred Edmund Brehm, Bird-life, tr. by H.M. Labouchere and W. Jesse, page 866
4. Used other than figuratively or idiomatically: a witch who lives in, controls, is able to dowse or find, or is otherwise connected with, water.
   • […] plays with the stormy petrel, / And answers the sea-gull's call. […] the water-witch, gray and ancient, / And hearing the tales she tells.1890, Katharine Pyle, “The Sea Princess”, in St. Nicholas: An Illustrated Magazine for Young Folks, page 824