Introduction

Widespread in the Americas, with a striking appearance and a variety of loud and unusual calls, the Common Moorhen is a rail the size of a small duck, with short tail and wings, long toes, and (in the adult) a short, bright-red-and-yellow bill. Sexes are similar in plumage. This species is ecologically and behaviorally intermediate between the American Coot and the rails, and it resembles the Purple Gallinule in certain respects. It breeds throughout much of the eastern United States and locally in the West, wintering in southeastern and southwestern states with the largest concentration in Florida. There is an endemic subspecies in the Hawaiian Islands. Individuals are territorial in the breeding season but somewhat gregarious in winter. Closely associated with marshes, ponds, canals, ditches, and rice fields where pools with submerged or floating vegetation are interspersed with emergent or shoreline vegetation, this species forages for plant materials and macroinvertebrates on the water surface, among submerged plants, and in shoreline and upland vegetation. Its diet and foraging modes are diverse. In some regions, moorhens use altered, artificial, agricultural, or urban habitats, including small ponds, during the breeding and nonbreeding seasons.

Most American research on this species has been conducted in the southern United States, especially Louisiana and Florida, where moorhens are more common and conspicuous than in the North and West. Diet has been well studied in Florida (Mulholland and Percival 1982, O’Meara et al. 1982, Haag et al. 1987), and breeding biology in Louisiana (Bell and Cordes 1977, Matthews 1983, Helm et al. 1987). Although tolerant of urban and agricultural habitats, pollution and alteration of wetlands constitute potential threats to this bird. Relationships between vegetation structure and this species, including the effects of muskrats and other herbivores on habitat and the impacts of plant invasions, need study. Common Moorhens are hunted in the conterminous 48 states; little is known about how this affects populations.

The Common Moorhen is widely distributed in Europe, where it has been the subject of a substantial literature (synthesized by Cramp and Simmons 1980), especially cooperative breeding (Gibbons 1986, 1987; Eden 1987, Leonard et al. 1989) and conspecific brood parasitism (McRae 1995, McRae and Burke 1996). There has been no comparative study of behavior or ecology of the moorhen in Europe, America, and the Hawaiian Islands.

Historically known as the Common Gallinule, Florida Gallinule, and Black Gallinule in the United States, this bird is called Moorhen (formerly Water-hen) in England. This account focuses on the continental North American subspecies Gallinula chloropus cachinnans and the endangered subspecies G. c. sandvicensis of the Hawaiian Islands.

The Common Moorhen’s striking appearance, loud and varied calls, and “tameness” in many situations have attracted popular attention. The moorhen has appeared in literary works by authors as diverse as Virginia Woolf (“The Mark on the Wall” in Monday or Tuesday, 1921) and Maeve Binchy (The Glass Lake, 1995) , and was featured on a postage stamp from Tristan da Cunha, in the South Atlantic. In native Hawaiian mythology, a moorhen brought fire to humankind, its forehead scorching red in the act.