Water Rail - Predators and Parasites

Predators and Parasites

Predators of the Water Rail include a number of mammals and large birds. The American mink was partly responsible for the extinction of the Icelandic population, and cats and dogs have also been recorded as killing this species. At least locally, otters will also eat rails and other water birds. The Eurasian Bittern, another reed bed bird, will consume rails, as will Grey Herons. Water Rails are particularly vulnerable to the heron when forced out of the cover of the reeds by very high tides. Wetland-hunting harriers are predictable predators, but more unusually, the rail has also been recorded as a prey item of the Tawny Owl, Short-eared Owl, Eurasian Eagle-owl, Greater Spotted Eagle, Common Kestrel, and night-hunting Peregrine Falcons.

Parasites include the sucking lice Nirmus cuspidiculus and Pediculus ralli, the tick Ixodes frontalis, and the louse fly Ornithomyia avicularia. The Water Rail can be infected by the avian influenza virus and the bacterium Borrelia burgdorferi, carried by Ixodes ticks, which is also a human pathogen causing Lyme disease. Three lice, Fulicoffula rallina, Pseudomenopon scopulacorne and Rallicola cuspidatus discovered on dead Water Rails in 2005 on the Faroe Islands were all species that had not been found on the archipelago previously. The parasitic flatworm Ophthalmophagus nasciola was found in one rail's nasal sinus, and at least three species of feather mite have been detected on the plumage. The louse Philopterus ralli and the nematode Strongyloides avium have been found on the subspecies R. a. indicus. The eastern subspecies is also one of the many intermediate hosts of another nematode, Gnathostoma spinigerum, which causes human gnathostomiasis, a disease found in Thailand, Japan and other parts of Southeast Asia. The nematode's first-stage hosts are copepods of the genus Cyclops, which are consumed directly or indirectly by a wide variety of vertebrates before maturing in the third and final host, a carnivorous mammal. The rail is therefore unlikely to be a source of human gnathostomiasis, which is normally caused by consuming raw or undercooked infected poultry, pork, freshwater fish, or by drinking water contaminated with infected Cyclops.