Porphyrio porphyrio

Geographic Range

Purple swamphens are native to the tropical and sub-tropical regions of Europe, Africa, Asia, and Australasia. They have been introduced to Florida. In Europe, purple swamphens live in the Atlantic and Mediterranean basins where there are suitable lagoons, rivers, and other wetlands. There are 13 recognized subspecies of purple swamphen.

• Biogeographic Regions
• nearctic nearctic
  • introduced introduced
• palearctic palearctic
  • native native
• oriental oriental
  • native native
• ethiopian ethiopian
  • native native
• australian australian
  • native native
• oceanic islands oceanic islands
  • native native

Habitat

Purple swamphens live in freshwater and brackish wetlands containing plenty of emergent vegetation. The vegetation often includes reedmace ( Typha ), sedges ( Carex ), and reeds ( Phragmites ). They prefer marshes and swamps with consistent water levels. They can also be found in pastures and disturbed areas. They spend most of their lives on the ground and are not interested in forests.

• Habitat Regions
• temperate temperate
• tropical tropical
• terrestrial terrestrial
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• coastal coastal
• brackish water brackish water

• Wetlands
• marsh marsh
• swamp swamp

• Other Habitat Features
• agricultural agricultural
• riparian riparian
• estuarine estuarine

Physical Description

Purple swamphens are large members of the rail family ( Rallidae ). Males are larger than females, males average 1,050 g and females 850 g. They are chicken-sized birds with dark, shiny indigo or purple feathers and red bills and frontal shields. Although plumage color varies regionally, in general their backs and wings are dark green, brown or black with a green sheen and their breasts and heads are from pale blue to purple blue. Their tails are short, and they have bright white feathers on the undersides of their tails. Their legs are long, scaly, and orange-red.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Purple swamphens use a variety of mating systems, ranging from monogamous mating to communal mating. In communal mating, two breeding females share one nest and are fertilized by several males. In addition to the parents, non-breeding helpers of both sexes help raise the young. These groups generally contain 6 to 9 birds and the helpers are usually close kin to the breeders. Dominance hierarchies in these groups exist and there is generally a dominant female that breeds the most. Some populations of purple swamphens are monogamous. The full range of mating systems can be found in other populations, including smaller social breeding arrangements consisting of 1 or 2 females, 1 or several males, and helpers at the nest or not.

Courtship in New Zealand populations begins in late July and continues until early December. Males use an elaborate courtship display where they hold reeds in their bill, bow, and emit a chuckling vocalization. Preening is a common behavior, and it is often invited by one bird preening and bowing while another approaches. Courtship feeding occurs more often in communal settings than in pairs. Copulation could be initiated by a bird giving a humming call or by the male chasing her. Copulation within communal settings involves every type of pairing possible, including heterosexual, homosexual, and multiple participants. Group mating activity appears to have a function in synchronizing all the birds’ sexual cycles, thus allowing clutches to be laid and hatched simultaneously. Birds nesting in exclusive pairs copulate less than those in communal settings.

• Mating System
• monogamous monogamous
• polyandrous polyandrous
• polygynous polygynous
• polygynandrous (promiscuous) polygynandrous (promiscuous)
• cooperative breeder cooperative breeder

Males become sexually mature when they are three years old. They mate with the two oldest and most dominant females in their group. Two to seven breeding males are possible in one communal breeding group. Young from previous seasons may be present to help with rearing the young. Both sexes of parents, but not sexually immature helpers, incubate the eggs. If a helper is old enough to breed but didn’t, it may help incubate near the end of the incubation period. Because of this system, yearling birds encounter their first hatchlings while under the supervision of more experienced birds. Non-breeders two or three years old have already had at least one year experience with young, and the parents themselves have had three or more years experience raising young. It appears raising chicks is partly a learned behavior, since non-breeders observe and learn how to provision the young. They build nests out of grass and tussock and sometimes both breeding females lay in the same nest. Neither female attempts to damage the other female’s eggs. The eggs hatch within four days of each other and the hatchlings are ready to leave the nest after about two days. They are brooded for a week and parents and helpers feed them until they are about ten weeks old. Breeding groups often attempt a second brood in a season, but these broods are not often successful.

Males build several nests. The ones built early in the season appear to be practice nests, as they are poorly constructed and lack a well-shaped bowl. They use stems of Typha and Juncus and tussocks of Carex and Cyperus . Nests are protected by a canopy of plants and are accessible by a ramp. After hatching, males then construct new nests specifically for brooding. Nests made of Typha are preferred for this purpose. Brood nests are often abandoned in favor of ones built nearer feeding sites.

Females usually lay their eggs around dawn. Females sharing a nest typically lay their eggs on the same days. Clutches are laid between mid August and mid February. Most breeders lay one or two clutches per season, but if a clutch is lost, extra clutches will be laid to make up for it. Each female will lay 3 to 6 eggs per clutch, with up to 12 eggs in a communal nest. Dominant females lay at least one egg more than submissive females when in communal settings. Incubation begins when half the clutch is laid, so individual eggs will end up hatching between 23 and 29 days after being laid. Hatching occurs over a two to three day interval. Only adults incubate, and females incubate more than males. In communal settings, the dominant female incubates the most. Interestingly, in group settings females will incubate most often during the day and allow males to concentrate on defense. Males are better at defense and incubate at night, when they aren’t needed for protection. In pair settings, this division of labor is difficult to implement and nest defense is not as effective.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Purple swamphens generally have help when raising young. Monogamous pairs are often assisted by the young they’ve raised from earlier broods. Promiscuous mating groups all help each other. Also, both of the above groups may receive aid from non-breeders of either sex and different ages. When young hatch they are nidifugous and precocial. During the hatching period, one parent will sit on the nest and the hatched chick(s) while others bring food to feed the sitter or the young. Within three days new hatchlings are led away from the nest and fed elsewhere, sometimes on floating platforms of aquatic vegetation. Hatchlings begin to eat on their own after two days, but are still fed by adults until they are two months old. Hatchlings learn to stay close to cover and whenever a predator is spotted adults rush to protect the young. In pair territories, the young become independent earlier because their parents re-nest and hand over care to helpers.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

There is little information on lifespan in purple swamphens in the literature. In New Zealand the oldest recorded pukeho was 9 years old. The related American species, Porphyrio martinica , has been recorded living up to 22 years in the wild.

Behavior

Breeding birds defend a home range to the exclusion of other purple swamphens. Resident birds have an equal sex ratio and all of them, juveniles included, assist with territorial defense. Groups usually have a stable membership, but some groups which are formed early in the breeding season and which have too many males may change membership. The members of the groups arrange themselves into a dominance hierarchy using sex and age as factors to determine each other’s place. When juveniles grow up in a communal breeding setting, they will remain in their natal territories after maturity. When juveniles have been raised by pairs, however, they leave their natal territory when nesting begins the next season.

Purple swamphens prefer to run or swim but will attempt to fly if necessary. They are poor fliers, their take-offs are difficult and their long legs dangle awkwardly while they are airborne. Their landings are more controlled crashes, and they often try to cushion themselves by falling on a shrub.

• Key Behaviors
• cursorial
• terricolous
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social
• dominance hierarchies dominance hierarchies

Home Range

Home range sizes are not reported for purple swamphens.

Communication and Perception

Purple swamphens communicate visually and with vocalizations. Their calls are varied, including their shrieking warning and attack calls and their hummed courtship calls. They also use a flash of their white rumps to tell predators they’ve been spotted.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Purple swamphens eat vegetable matter and small animal prey. They eat the bulbs of Scirpus plants and browse on the shoots of marsh grasses and reeds. Animal prey is usually arthropods and other invertebrates, such as snails, although they occasionally take vertebrate prey, including fish, birds, and lizards. When they eat birds, they generally eat eggs, nestlings, and juveniles. They have been recorded preying on passerines and waterfowl , including teal, swans, and ducks. They also swallow grit, like sand or other sediment, to help their gizzards grind up their food. They sometimes lift food to their mouths with their feet, rather than eating it on the ground.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• amphibians
• reptiles
• fish
• eggs
• insects
• terrestrial non-insect arthropods
• mollusks

• Plant Foods
• leaves
• roots and tubers

Predation

Purple swamphens are one of New Zealand’s most successful bird species because they have appropriate responses to terrestrial mammalian predators. New Zealand has no native terrestrial predators, so many native New Zealand birds are very vulnerable to predation by introduced mammalian predators. One of their responses to predators is to physically attack the predator. They also use wing flapping, calls, and flashing their white rump patches to alert conspecifics to the presence of a predator and disturb the predator itself.

Purple swamphens use a conspicuous rump patch to signal their awareness of a predator’s proximity. To call attention to the patch, they flick their tails up and down rapidly. Interestingly, it appears the signal is not meant to alarm other swamphens as much as it is meant to tell the predator it’s been spotted. If the prey communicates its awareness of the predator’s presence, the predator may be less likely to attempt a pursuit. Also, purple swamphens have been noted to signal their awareness less when they are closer to cover. This may be due to decreased vigilance or to the lower visibility of the signal when the swamphen is close to cover.

Sometimes purple swamphens form groups to mob stoats and rats. The shrieking calls they emit during these hunts are called “blue murder” by overhearing humans. When not attacking, they will flee.

Ecosystem Roles

Purple swamphens are important predators of marsh invertebrates and impact marsh communities through their predation and browsing.

Economic Importance for Humans: Positive

Purple swamphens eat pest insects in crop areas. They also hunt and kill rats and stoats.

Because they are the closest relatives of endangered takahes ( Porphyrio hochstetteri and Porphyrio mantelli ), purple swamphens are valuable research animals for takahe conservation. One problem plaguing takahe is their low fertility rates. Gunn et al. (2008) performed experiments to find out what was the best method to retrieve sperm from purple swamphens. Perfecting artificial insemination in swamphens may make it easier to help takahe with their breeding needs. Purple swamphens may also be valuable as potential foster parents to takahe. Unlike purple swamphens, takahe do not possess good responses to terrestrial predators. This lack of response has caused serious declines in their populations since the introductions of mammalian predators. Bunin and Jamieson (1996) took one takahe chick and placed it with purple swamphens. This cross-fostered chicks grew up to display swamphen responses, including increased vigilance and tail flicking.

• Positive Impacts
• research and education
• controls pest population

Economic Importance for Humans: Negative

Purple swamphens eat crop and pasture plants, including potatoes, kumara, clover, and grass.

• Negative Impacts
• crop pest

Conservation Status

Purple swamphens are not considered threatened from a global viewpoint. However, in Europe populations have declined as a result of habitat loss. They are considered rare and protected species throughout most of Europe. In Portugal they are considered endangered and they have been extirpated from parts of their former range. Hunting of purple swamphens is illegal, although hunters sometimes mistake them for legal gamebirds, like common coots ( Fulica atra ) and moorhens ( Gallinula chloropus ). Because they don’t move far by flying, they don't readily colonize available habitat that is isolated. In some areas more suitable wetland habitats are being created as a result of human expansion. Rice fields built along the Guadalquivir river encourage growth of Typha and Phragmites . New reservoirs result in build up of silt layers and the formation of new marshes. Reintroductions are also being attempted. European populations seem to be recovering.

Other Comments

It is thought that ancestral purple swamphens colonized Australasian islands, where these isolated populations evolved to become endemic swamphens and takahe: Porphyrio albus , Porphyrio hochstetteri , and Porphyrio mantelli .

Purple swamphens were kept as decorative birds by Romans and are one of the few bird species they did not eat.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Aqua Nara Dakota (author), Special Projects.

References

Alvarez, F. 1993. Alertness signalling in two rail species. Animal Behavior , 46: 1229-1231.

Balasubramaniam, S., P. Guay. 2008. Purple Swamphens ( Porphyrio porphyrio ) Attempting to Prey upon Black Swan ( Cygnus atratus ) Eggs and Preying upon a Cygnet on an Urban Lake in Melbourne, Australia. The Wilson Journal of Ornithology , 120 (3): 633-635.

Bunin, J., I. Jamieson. 1996. Responses to a Model Predator of New Zealand's Endangered Takahe and Its Closest Relative, the Pukeko. Conservation Biology , 10 (5): 1463-1466.

Celdran, J., F. Polo, V. Peinado, G. Viscor, J. Palomeque. 1994. Haematology of captive herons, egrets, spoonbill, ibis and gallinule. Comparative Biochemical Physiology , 107A: 337-341.

Craig, J. 1980. Pair and group breeding behavior of a communal gallinule, the pukeko, ( Porphyrio p. melanotus ). Animal Behavior , 28: 593-603.

Freifeld, H., D. Steadman, J. Sailer. 2001. Landbirds on offshore islands in Samoa. Journal of Field Ornithology , 72 (1): 72-85.

Gomez, G., R. Baos, B. Gomara, B. Jimenez, V. Benito, R. Montoro, F. Hiraldo, M. Gonzalez. 2004. Influence of a Mine Tailing Accident Near Donana National Park (Spain) on Heavy Metals and Arsenic Accumulation in 14 Species of Waterfowl (1998 to 2000). Archives of Environmental Contamination and Toxicology , 47: 521-529.

Gunn, M., Z. Champion, M. Casey, P. Teal, P. Casey. 2008. Testicular and spermatozoan parameters in the pukeko ( Porphyrio porphyrio melanotus ). Animal Reproduction Science , 109: 330-342.

Jamieson, I., J. Craig. 1987. Male-Male and Female-Female Courtship and Copulation Behavior in a Communally Breeding Bird. Animal Behavior , 35 (4): 1251-1253.

Jamieson, I. 1988. Provisioning behavior in a communal breeder: an epigenetic approach to the study of individual variation in behavior. Behavior , 104 (3-4): 262-279.

Jamieson, I. 1997. Testing reproductive skew models in a communally breeding birds, the pukeko, Porphyrio porphyrio . Proceedings of the Royal Society of London B , 264: 335-340.

Olliver, N. 2008. "New Zealand Birds" (On-line). Pukeko. Accessed January 19, 2009 at http://www.nzbirds.com/birds/pukeko.html .

Pacheco, C., P. McGregor. 2004. Conservation of the purple gallinule ( Porphyrio porphyrio L.) in Portugal: causes of decline, recovery and expansion. Biological Conservation , 119: 115-120.

Sanchez-Lafuente, A., P. Rey, F. Valera, J. Munoz-Cobo. 1992. Past and current distribution of the purple swamphen Porphyrio porphyrio L. in the Iberian Peninsula. Biological Conservation , 61: 23-30.