Purple Gallinule Life History

Habitat

Purple Gallinules inhabit freshwater marshes, mostly places that hold water year-round and that have sedges, grasses, and rushes and especially also dense stands of emergent floating vegetation such as American lotus, water shield, spatterdock, pickerel weed, arrowhead, water pennywort, and various water lilies. These floating plants provide habitat both for foraging and nesting. Nonbreeding birds are often seen in more open environments than breeding birds, which require more extensive aquatic vegetation for suitable nest sites. Purple Gallinules use lakes, ponds, impoundments, reservoirs, and wet rice fields to varying extents, so long as there is food and adequate vegetation for cover and foraging. In South America, migrants have been found in Andean wetlands at elevations as high as 13,385 feet. Migrating individuals crossing the Gulf of Mexico often appear on oil drilling platforms, on barrier island beaches, and in gardens.

Food

Like most rails, Purple Gallinules eat a great variety of foods; typically more plants than animals. The water-lily family, including American lotus, produces flowers and fruits that gallinules consume readily, and they also eat flowers, leaves, and tubers of invasive exotic plants such as water hyacinth and hydrilla, as well as rice. Seeds of many different sedges and other aquatic plants such as buttonbush, water willow, sawgrass, smartweed, and pickerel weed are also important food items. Purple Gallinules also prey on spiders, mollusks, beetles, bees, worms, snails, dragonflies, leeches, ants, grasshoppers, and moth larvae, as well as frogs, small fish, and eggs and nestlings of other birds.

Nesting

Nest Placement

Nests and their placement vary tremendously: some are loose collections of vegetation made of, and on, floating vegetation, and these move around during windy periods. Others are anchored in reeds or other emergent vegetation, placed near water level or in vegetation as high as 2.6 feet above the water. Purple Gallinules build up to 4 different nests, though only one is used for egg-laying and incubation. Because the sexes are similar, it is not known which sex selects the nest, but both male and female apparently participate in construction.

Nest Description

The nest is a roughly cup-shaped platform of rushes, sedges, and grasses, normally fixed into a crotch of standing marsh vegetation or onto floating vegetation. Nests are roughly 11 inches across and 3.5 inches deep. Some nests have a half-roof, to conceal the incubating parent and provide some protection from the elements. Others have a small ramp of vegetation leading to the nest. When young hatch, a parent sometimes moves them to one of the additional nests.

Nesting Facts

Behavior

Foraging Purple Gallinules recall a chicken, albeit one with very long legs; they usually walk slowly and carefully, placing the feet gingerly as they survey marsh vegetation for edible plants and animals. As they walk, they often flick the tail up and down like a chicken does. When disturbed they run, swim, or fly away, legs dangling, sometimes landing in trees or shrubs, where they readily climb, balancing with their wings as they move about. Swimming birds jerk the head forward rhythmically as they proceed. They can also dive underwater, remaining hidden except for the bill for long periods. Young birds learning to walk on floating vegetation often appear comical, holding their wings high in the air and racing across the pads quickly when called by a parent. Adults sometimes clash over territories, first posing in erect posture, then chasing and, rarely, striking each other with feet and bills unless one bird assumes a submissive posture. During such fights, birds call loudly. Rival males also sometimes strike a bowing pose during or after conflict, with lowered neck and head, raised body and tail, with wingtips touching over the back. Nesting pairs appear to be seasonally monogamous in the United States and defend territories of about 2.5 acres. Nonbreeding birds are usually found in areas less suitable for nesting, and they are not territorial. Purple Gallinules often nest in the same areas as Common Gallinules, which appear to be dominant over them.

Conservation

Overall, Purple Gallinule populations in the U.S. have decreased slightly or held steady from 1966–2019, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 390,000 and rates them 12 out of 20 on the Continental Concern Score, indicating a species of relatively low conservation concern. In the southeastern coastal plain of the U.S., however, numbers have declined dramatically. The U.S. Fish and Wildlife Service carefully monitors waterfowl hunting from year to year, and hunted species include Purple Gallinules and Common Gallinules (although most Purple Gallinules migrate out of their breeding habitat before the beginning of hunting season). Records indicate that each year hunters take a total of about 10,000 of the two species combined. Because they’re wetland birds, Purple Gallinules are vulnerable to declines in water quality including changes in water levels, pollution, and runoff. Loss of wetland habitat from draining or conversion to other uses is also a problem. Clearing of vegetation from wetlands to create more open water may make habitat less suitable for Purple Gallinules. Faster-maturing varieties of rice may not give Purple Gallinules enough time to raise their young before harvest. On the other hand, invasive plants such as water hyacinth and hydrilla, which have created serious problems for some wetland species, may actually improve food supplies for Purple Gallinules.

Credits

Farnsworth, A., F. A. La Sorte, and M. J. Iliff. (2015). Warmer summers and drier winters correlate with more winter vagrant Purple Gallinules (Porphyrio martinicus) in the North Atlantic region. Wilson Journal of Ornithology 127:582–592.  .

Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA.

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.

Raftovich, R. V., S. C. Chandler, and K. K. Fleming. (2018). Migratory bird hunting activity and harvest during the 2016-17 and 2017-18 hunting seasons. U.S. Fish and Wildlife Service, Laurel, MD, USA.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

West, Richard L. and Gene K. Hess. (2002). Purple Gallinule (Porphyrio martinica), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Wood, C. L. (1999). Changing seasons: spring migration. North American Birds 53:247-251.

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