Gallinula galeata (Lichtenstein, 1818)
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Basis for Listing
The common gallinule is distributed nearly worldwide, occurring in North, Central, and South America, Europe, Asia, Australasia, Africa, and the Hawaiian Islands. In North America, its range covers much of the eastern United States, small areas of the southwestern United States, small portions of southeastern Canada, and most of Mexico. In the United States, the largest wintering concentrations of common gallinules can be found in Florida (Bannor and Kiviat 2002). In Minnesota, the common gallinule appears to have declined during the past 50 years, and recent nesting records and sightings are rare.
Largely slate gray in coloration, the common gallinule is similar in appearance to the American coot, a much more common species in Minnesota. The common gallinule is best distinguished from the coot by a line of white streaks on the gallinule's sides, which appears as a white line on a swimming bird. Adult common gallinules also have a bright red shield above their bill, which blends into a red bill with a yellow tip. American coots have a whitish bill. Common gallinule vocalizations are varied and hen-like, with a combination of cackles, squawks, yelps, and clucks (Bannor and Kiviat 2002). The gallinule's call resembles that of the American coot, but it has been described as sharper and higher pitched. Additionally, the common gallinule is more likely to stay in the cover of dense vegetation rather than swim in open water like the coot.
Freshwater cattail-bulrush marshes are the domain of this species. Higher common gallinule abundance and breeding density have been associated with a number of marsh features, including large size, deep water, equal parts open water and emergent vegetation, abundant dead vegetation, floating islands of organic matter, and abundant muskrat (Ondatra zibethicus) runways (Bannor and Kiviat 2002). In some areas, gallinules share similar habitat with American coots. Large, expansive wetlands are not essential for common gallinules , as this species will utilize quiet rivers, lakes, ponds, and small marshes along the edges of lakes or rivers. In some regions, common gallinules may also use artificial habitats, such as rice fields and sewage lagoons. They can be sensitive to human disturbance, however, moving away from areas frequently used by people (Bannor and Kiviat 2002).
Biology / Life History
The common gallinule is a freshwater marsh rail. It feeds while swimming, diving, or walking on emergent vegetation. Common foods include seeds, soft plant parts, rootlets, snails, and insects (NatureServe 2011). It is a nocturnal, short- to medium-distance migrant, even in areas of more permanent residence (Bannor and Kiviat 2002). Outside of migration, the common gallinule rarely flies (NatureServe 2011). When threatened, it tends to hide within emergent vegetation. The species returns to its breeding grounds in late April through late May. A pair generally forms a seasonal bond before setting up a territory. Both sexes are highly territorial during the breeding season, engaging in aggressive displays to warn off intruders. However, common gallinules are often seen in family groups, and are social on their winter grounds (Bannor and Kiviat 2002). The pair builds a cup-like nest made of stems and leaves. These nests are often constructed on top of bent or dead cattails, in thick emergent vegetation close to open water. Common gallinules and American coots choose nest sites with similar features, suggesting the possibility of inter-specific competition (Bannor and Kiviat 2002). Eggs vary greatly in size, shape, and color. Clutch size also varies, with roughly 5-10 eggs per nest. Common gallinules in the northern United States may have 1-2 broods per season. Incubation lasts between 19-22 days, with both sexes incubating the eggs (Bannor and Kiviat 2002). After hatching, chicks are semi-precocial, leaving the nest and following the adult after 12-24 hours. They are able to feed themselves at 7 days, and are completely self-sufficient at 21-25 days. Common gallinules can breed within a year of hatching.
Conservation / Management
Wetland protection is vital to maintaining common gallinule populations. This species requires marshes with a nearly equal interspersion of emergent vegetation and open water (Greij 1994). Many marshes in Minnesota lack the necessary open water component, and therefore are currently unsuitable for common gallinules. The gallinule's secretive nature combined with annual changes in marsh vegetation make population surveys difficult. Possible threats to this species include human disturbance and development, wetland drainage and degradation, predation, pollution, non-native plant invasions, and changes in muskrat populations. More studies are necessary to determine impacts of each of these factors on common gallinule populations (Bannor and Kiviat 2002). The common gallinule is a game species in some areas of North America. Most hunting occurs in Louisiana, Florida, and Texas, states in which the species over-winters. Hunting pressures on wintering grounds may play a role in the decline of common gallinules that breed in Minnesota (Bannor and Kiviat 2002).
Conservation Efforts in Minnesota
Bird surveys by the Minnesota Biological Survey found common gallinules to be relatively common in the extensive marshes along the Mississippi River in Houston County. Common gallinules have also been found at scattered locations elsewhere in southern and central Minnesota, but the species' current distribution and abundance in much of southern Minnesota remains poorly understood. Marsh preservation and restoration programs undoubtedly benefit the common gallinule, as well as many other marsh species. Development of a more complete understanding of the common gallinule's distribution, abundance, and habitat preferences in Minnesota remains a priority.
References and Additional Information
Bannor, B. K., and E. Kiviat. 2002. Common Moorhen (Gallinula chloropus). Number 685 in A. Poole and F. Gill, editors. The birds of North America. The Birds of North America, Inc., Philadelphia, Pennsylvania.
Greij, E. D. 1994. Common Moorhen. Pages 145-157 in T. C. Tacha and C. E. Braun, editors. Migratory shore and upland game bird management in North America. International Association of Fish and Wildlife Agencies, Washington, D.C.
NatureServe. 2011. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia.
Roberts, T. S. 1932. Birds of Minnesota. Volume 2. University of Minnesota Press, Minneapolis, Minnesota; London, H. Milford, Oxford Universtiy Press.