SPECIES

Purple Gallinule Porphyrio martinica

Richard L. West and Gene K. Hess
Version: 1.0 — Published March 4, 2020
Text last updated January 1, 2002

Diet and Foraging

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Feeding

Main Foods Taken

Vegetable matter selected from seeds, flowers, fruits, and other nutritious parts of aquatic plants. Common food items include seeds of annual grasses and sedges, seeds of floating and submergent vegetation, flowers of water hyacinth and domestic rice grains (Helm 1994). Consumes animal material when available, especially arthropods, annelids, and mollusks, sometimes >50% of diet in spring and summer (Mulholland and Percival 1982).

Microhabitat For Foraging

Feeds in a circular pattern near periphery of emergent vegetation (Bell 1976). In a Florida study, largely found in areas which contained spatterdock beds; fed while standing on floating-leaved vegetation and avoided open water (Mulholland 1983). In a s. Texas study, fed 86% of time in Panicum and Paspalum grasses, 14% in cattail.

Food Capture And Consumption

Individuals of all ages spend much time walking or running about on lily pads, frequently rolling back edges of pads with their bills, stepping on them and holding them in that position as they pick off aquatic insects from undersides (Stoddard 1978). Bends down or climbs stalks of rice and other grains to feed on seed heads. Also obtains food in bushes and trees (Bent 1926, Oberholser 1974). Takes berries on shore (Stiles and Skutch 1989). In a comparative study with Common Moorhen, Purple Gallinule was observed feeding from a standing position 99.7% of the time (n = 594); Common Moorhen fed from a sitting (swimming) position 94% of the time (n = 1,789; Reagan 1977). Purple Gallinule selects dense portions of grass communities, while Common Moorhen is generally associated with open water or sparse grasses.

In order to reach an American lotus seed pod, individual climbs stalk, bending it over near water and pecking through soft, fibrous underpart of pod. Unripe seed is extracted, tough leathery outer hull removed, and contents eaten (Olson 1963). Feeds on blossoms of water hyacinth by taking small, rapid bites, often only 1 or 2 bites from a flower and then starting on another blossom without finishing the first (Crosby 1969).

Hammers the tough skin of water lily (Nymphaea ampla) tubers, a principal food in Costa Rica, with its bill for 2–3 min to get at the pink-white pith of the tuber. Then obtains bites by hammering at hard pith with bill open, twisting bill upon impact with pith, feeding for 10–15 min on a tuber. Chicks unable to open tubers before 6 wk of age (Hunter 1986). In Costa Rica, feeds on wild plantain (Heliconia elongata) by holding down thick, fleshy bract with toes and tearing it open to extract the developing fruit even before it ripens and emerges.

Nineteen frogs observed taken by 3 families in Costa Rica. Each time a frog was caught, most or all members of the family tried to obtain a piece; ≥2 individuals often pulled at opposite ends of frog's body. Individuals that ran off with a piece of the frog were chased by other family members. On 10 occasions, this activity persisted for 8–23 min (Krekorian 1978). Individual reported taking a nestling Snowy Egret (Egretta thula) by landing on its back, grasping it in its feet, and severing its spinal cord before flying off with nestling in its bill. Also carried off (in its bill) a heron egg (McIlhenny 1934). Took a Wood Duck (Aix sponsa) chick by first breaking its neck and then proceeding to open its back; another flew off with a still-living, half-grown Common Grackle (Quiscalus quiscula) nestling in its bill, carried it to the bank, opened its back, drew out sections of viscera, and then tore off bits of flesh. Another pulled apart a young heron held under its feet; began to eat viscera, and then flew with carcass to avoid being robbed by another gallinule. Another opened an Anhinga (Anhinga anhinga) egg and drew out a developed embryo (McIlhenny 1936a).

Diet

Major Food Items

Varies greatly with seasonal and local availability, but over time, plant food predominates over animal (Howell 1932, Mckay 1981, Mulholland and Percival 1982). Flowers and fruits of the water-lily family are plentiful at many sites and become the major food (Mckay 1981, Mulholland and Percival 1982, Hunter 1986). Two invasive exotic plants in s. U.S. can become staples—water-hyacinth flowers and hydrilla leaves and tubers (Mulholland and Percival 1982, Esler 1990, Helm 1994, RLW).

Main food of an individual collected in s. U.S. were 5 frogs (average 6.4 cm long); a leech (Hirudinea) and insect and plant fragments also present (Audubon 1838b). American lotus a staple food in Leon Co., FL, and S. Carolina (Olson 1963). Sometimes known as the “Plantain Coot” from its fondness for that fruit (Jamaica; Gosse and Hill 1847).

Quantitative Analysis

Diet in a Florida pond averaged 71% plant material (mostly seeds) and 29% animal matter (Mulholland and Percival 1982; see Table 1). These amounts of plant and animal foods almost identical to diet of Purple Gallinules nesting in Colombian rice fields (Mckay 1981) and Apr data agree with a Florida spring study by Howell (Howell 1932). That study of stomach contents of 7 birds indicated a diet of 42% by volume animal matter, 58% vegetable; animal matter—frogs, mollusks (Mollusca), water beetles, (Coleoptera) grasshoppers (Orthoptera), leaf beetles (Chrysomelidae), ants (Formicidae), bugs (Hemiptera), dragonflies (Anisoptera), and spiders (Araneae); vegetable—seeds of buttonbush, water willow (Decodon verticillatus), primrose willow (Jussiaea), saw grass (Cladium jamaicense), smartweed (Polygonum), sedges (Cyperus, Carex), yellow pond lily (Nymphaea), and pickerel weed (Howell 1932).

In Costa Rica, Nymphaea fruit abundant and food most frequently eaten—71% of food items identified at time of eating. In addition, stingless bees (Trigona spp. 16%), frogs (7%), grass seeds (2%, Leersia hexandra on islands and Paspalum virgatum on shore), spiders, worms, and fish also eaten (Krekorian 1978). In Colombian rice fields, rice grains constituted 68% of adult diet by volume of all but 1 of stomachs examined; remainder made up of rice-field weed seeds (5%) and animal matter (27%), the most frequent being borer moth (Nictate) pupae and larva, dragonfly (Adinida) adults and nymphs, and various beetles (Coleoptera; Mckay 1981).

Food Selection and Storage

No data on selection. Sexes did not differ in volume of plant material consumed in a Colombian rice field, but females consumed more animal material (mean 1.9 ml for females, 0.1 ml for males (Mckay 1981). Not known to store food.

Nutrition and Energetics

No information.

Metabolism and Temperature Regulation

No data. Controls temperature by rapid respiration (open bill) while shading eggs (Gross and Van Tyne 1929).

Drinking, Pellet-Casting, and Defecation

No information.

Recommended Citation

West, R. L. and G. K. Hess (2020). Purple Gallinule (Porphyrio martinica), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.purgal2.01