Taxonomic name: Porphyrio porphyrio Linnaeus, 1758
Common names: bláhæna (Icelandic), caimão (Portuguese), calamón común (Spanish), Modrzyk (Polish), pollo sultano (Italian), pukeko (Maori-New Zealand), purperkoet (Dutch), purpurhöna (Swedish), Purpurhuhn (German), seikei (Japanese), slípka modrá (Czech), sultanhøne (Danish), sultanhøne (Norwegian), sultánka modrá (Slovak), sulttaanikana (Finnish), talève sultane (French)
Organism type: bird
The ecological similarity of the purple swamphen (Porphyrio porphyrio) to the Florida native common moorhen (Gallinula chloropus) and purple gallinule (Porphyrula martinica) have prompted efforts to eliminate this member of the rail family from Florida. It is not clear what negative consequences could result from these non-native birds but in other parts of the world they are noted for their aggressive behaviour and their habit of eating other bird's eggs.
The purple swamphen (Porphyrio porphyrio) is a large rail which weighs on average 850 g (female) to 1050 g (male) (Balasubramaniam & Guay 2008). Purple swamphens have a clumsy gait when running and somewhat resemble large, purple, skinny chickens (Pearlstine & Ortiz 2009). Purple swamphens have large red bills and frontal shields, red irides, orange legs and toes, usually with blackish areas at the heel and toe joints, white undertail coverts, and bodies that are pale blue, brilliant blue, purplish, or blackish (del Hoyo et al. 1996, Beaman & Madge 1998, as cited in Pranty et al. 2000). Australian birds are darkest, with blackish wings and backs; Phillipine birds are the palest and have rusty backs; and African birds have greenish backs; juvenal plumage is characterised by dull plumage and a dusky bill and frontal shield (del Hoyo et al. 1996, Beaman & Madge 1998, as cited in Pranty et al. 2000). Both sexes are similar, with females just slightly smaller; females also possess a smaller frontal shield (Pearlstine & Ortiz 2009). Juveniles are both duller-colored and paler than adults and may easily be confused with young of other related species, especially just after hatching, when all rails look like little black or brown fluffballs (Pearlstine & Ortiz 2009).
Purple swamphen eggs vary in shape, texture, and color; they may be long, oval, or elliptical; the surface may be smooth, glossy, or slightly rough; eggs come in an array of colors such as pale green, yellow-stone, creamy-white, pink, spotted, blotched, maroon, purple, and violet (eggs found in south Florida have been tan with brown spots) (Source: Pearlstine & Ortiz 2009).
In their native range, purple swamphens are known to be very vocal, with a repertoire of calls that includes a common, trumpeting call with a nasal rattle - quinquinkrrkrr - and a wide variety of groans, wails, squawks, shrieks, and hums (Johnson & McGarrity 2009). When displayed, their long and powerful song consists of nasal rattles that crescendo and is territorial in nature (Pearlstine & Ortiz 2009). Purple swamphens are quite terrestrial and will walk and climb readily but don't usually swim (Pearlstine & Ortiz 2009). They can be seen flying between areas in rice fields where groups are present (Pearlstine & Ortiz 2009).
Gallinula chloropus, Porphyrio martinica
estuarine habitats, riparian zones, water courses, wetlands
The purple swamphean lives in marshes, lagoons, and reservoirs with appropriate vegetation cover and water depth. Areas with tall, thick vegetation cover and shallow calm water are generally preferred (Cramp & Simmons 1980, Sanchez-Lafuente et al. 1998, as cited in Doss et al. 2009). They inhabit a wide variety of wetland habitats and they are found in ponds, lakes, dams, marshes, swamps, rivers, floodplains, rice fields, and water treatment ponds (Johnson & McGarrity 2009). The species also extends into open habitats adjacent to wetlands including grasslands, agricultural land, parks, gardens, and road and forest edges (Johnson & McGarrity 2009). They prefer permanent extensive wetlands with floating mats of water-lilies, tall, dense emergent vegetation (e.g. reeds Phragmites spp., Typha spp., sedge Carex spp., papyrus Cyperus spp., Scirpus spp. or Eleocharis spp.), muddy or sandy shorelines and patches of shallow water (Birdlife International 2009). They may occur in saline, eutrophic or turbid wetlands, and may be found on small waters and seasonal or temporary wetlands (e.g. in Africa) (Birdlife International 2009). They usually inhabit lowlands, but have been found at laltitudes more than 3000 m above sea level (Johnson & McGarrity 2009).
In the Mediterranean region, the species is highly dependent on lowland fresh or brackish water wetlands with abundant emergent vegetation, such as reedmace (Thypha sp.), reeds (Phragmites sp.) and sedges (Carex sp.) (Cramp & Simmons 1980, del Hoyo et al. 1996, Sanchez-Lafuente et al. 1992 2001, as cited in Pacheco & McGregor 2004). In New Zealand the swamphen (or pukeko) is often seen on roadsides, in wetlands or near drainage ditches (Brown et al. 1986, Jamieson 1994, as cited in Washington et al. 2008).
In their native range, swamphens are often observed away from wetlands and can damage grain and vegetable crops (Ripley 1977, del Hoyo et al. 1996, in Pranty et al. 2000). They have also been observed preying on nestlings and adults of different passerine species (McKenzie 1967, Egan 1992, Fitzsimons 2003), as well as eggs (Binns 1953, Fitzgerald 1966, Brown 1997) and ducklings from different waterfowl species including chestnut teal (Anas castanea) (van Tets 1965), Pacific black duck (A. superciliosa) (Nixon 1983, Bonser 1984), domestic muscovy duck (Cairina moschata) (Lowe 1966) and black swan (Cygnus atratus) eggs and cygnets (as cited in Balasubramaniam & Guay 2008).
Purple swamphens are known to be highly territorial and aggressive, and often fight amongst themselves and with other species over food (Johnson & McGarrity 2009). In large numbers, these aggressive invaders could have negative impacts on native birds (Johnson & McGarrity 2009).
A recent introduction to Florida, the purple swamphen has expanded from coastal southeast Florida into the Everglades Conservation Areas, and has been observed on Lake Okeechobee. Its ecological similarity to the native common moorhen (Gallinula chloropus) and purple gallinule (Porphyrula martinica) have prompted efforts to eliminate this member of the rail family (Hardin 2007). It is not clear what negative consequences could result from the presence of non-native species such as these, but Avery and Moulton (2007) argue that while the opportunity exists to remove them from the Florida landscape, it should be done. It makes little sense to wait and study the situation to see what impacts might accrue. As management action is delayed, populations of these species will increase and spread, making it that much more difficult and expensive to implement effective corrective measures later (Simberloff 2003, in Avery & Moulton 2007).
The purple swamphens taxonomy is complex and inadequately studied; at least 13 subspecies are currently recognised, three of which could be elevated to species status (Taylor & van Perlo
1998, as cited in Doss et al. 2009). Although P. porphyrio is classified as globally Non-threatened (del Hoyo et al. 1996), the nominal subspecies P. p. porphyrio, which is found along the western Mediterranean and south Atlantic regions, is considered a SPEC 3, classified as Rare in Europe (Tucker & Heath 1994) and Endangered in Portugal (Portuguese Red Data Book, Cabral et al. 1990) (as cited in Pacheco & McGregor 2004).
Native range: The purple swamphen is a tropical and subtropical bird with several subspecies and a distribution extending across southern Africa, southern Asia, Papua New Guinea, Australia, and New Zealand (Marchant and Higgins 1993, as cited in Balasubramaniam & Guay 2008). The subspecies P. p. poliocephalus occurs in southern Asia, extending from Pakistan throughout the Indian subcontinent and east to Burma and southcentral China (Taylor & van Perlo 1998, as cited in Doss et al. 2009). The subspecies P. p. melanotus ranges from New Guinea through Australia and New Zealand. The subspecies P. p. porphyrio occurs in southern Europe and North Africa historically present in most coastal wetlands along the western Mediterranean and south Atlantic countries, namely Portugal, Spain, France, Italy, Tunisia, Algeria and Morocco (Cramp & Simmons 1980, Glutz von Blotzhein et al. 1973, Grussu 1999, Sanchez-Lafuente et al. 1992, as cited in Pacheco & McGregor 2004). It was driven to the verge of extinction in Portugal, Sardinia (Italy) and continental Spain and total extirpation in France, Greece, continental Italy, Sicily (Italy) and Balearic Islands (Spain) (Cramp & Simmons 1980, Grussu 1999; del Hoyo et al. 1996, Sanchez-Lafuente et al. 1992, Tucker & Heath 1994, as cited in Pacheco & McGregor 2004).
Known introduced range: Florida
Local dispersal methods
Natural dispersal (local): Purple swamphens occasionally move long distances (up to 1000 km; Grussu 1999, in Pranty et al. 2000).
Ecological concerns have prompted efforts to eliminate this member of the rail family from Florida's avifauna (Hardin 2007). Action was initiated in 2006 to limit the continued spread of the purple swamphen in south Florida and to remove it from the ecologically sensitive Everglades habitat and water treatment areas. An eradication effort using shotguns and actively chasing purple swamphens from airboats was pursued. Retrieval efforts were scheduled to continue to remove the remainder of the introduced population (Avery & Moulton 2007). The Florida FWC have killed over 3000 purple swamphens to date, mostly from Stormwater Treatment Areas and from Water Conservation Area 2B (areas south/southwest of the Arthur R. Marshall Loxahatchee National Wildlife Refuge) (Johnson & McGarrity 2009). The FWC is currently studying the movements of purple swamphens in order to collect information that will help to develop a long-term management plan (Johnson & McGarrity 2009).
The purple swamphen feeds on new grass shoots, invertebrates, berries and grains (Washington et al. 2008). Quantitative investigations into diets of purple swamphens in Australia and New Zealand demonstrated that this species is almost completely herbivorous; animal matter constitutes only a minor portion of the diet and is mainly represented by insects and arachnids (Carroll 1966, Norman & Mumford 1985, as cited in Balasubramaniam & Guay 2008). However, they have been reported to eat fish, lizards, and birds (Wheeler 1949, Oliver 1974, as cited in Balasubramaniam & Guay 2008). In their native range, they are known to eat the shoots, leaves, roots, stalks, flowers, and seeds of a wide variety of plants, including agricultural species such as rice and sugar cane (Birdlife International 2009; Johnson & McGarrity 2009). For example they are known to consume Typha spp., Scripus spp., rice, grasses, sedges, Rumex spp., Polygonum spp., water-lilies, clover Trifolium spp., fern Salvonia repens, bananas, tapioca and yam Dioscorea spp.) (Birdlife International 2009). They also consume animal prey, including molluscs, small crustaceans (isopods, amphipods and crabs), earthworms and leeches, adult and larval insects (Coleoptera, grasshoppers, Hemiptera, Diptera, Lepidoptera), fish and fish eggs, frogs and frog eggs, water snakes (Natrix maura), adult birds, bird eggs and nestlings, small rodents and carrion (Birdlife International 2009; Johnson & McGarrity 2009). In their introduced range in Florida purple swamphens have been seen eating stalks and other parts of horsetail (Equisetum spp.), cattail (Typha spp.), spikerush (Eleocharis spp.), and sedges (Rhynchospora spp.), as well as native snails, earthworms, birdseed, and garbage (Johnson & McGarrity 2009).
Purple swamphens have been intensively studied in Italy, Spain, and New Zealand (see Grussu 1999; Sanchez-Lafuente 1993 and Craig 1980, as cited in Doss et al. 2009). Clutch size of swamphens varies geographically, usually decreasing
with latitude: 3 - 7 (southern India; Doss et al. 2009); 3 - 5 (Spain; Manez 1997); 4 - 6 (Italy; Schenk 1993); 3 - 6 (Algeria; Moali & Isenmann 2000); and 2 - 10 (New Zealand; Craig 1980) (as cited in Doss et al. 2009). Incubation period also varies: 19 - 22 (southern India; Doss et al. 2009); 23 - 25 days (Spain; Manez 1997); 24 - 27 days (Italy; Schenk 1993); 22 - 26 days (Algeria; Moali & Isenmann 2000); and 23 - 27 days (New Zealand; Craig & Jamieson 1990) (as cited in Doss et al. 2009). Hatching success was reported as 61% (n=113; southern India; Doss et al. 2009); 45.2 - 57.9% (Sanchez-Lafuente et al. 1998); and 73% (New Zealand Craig 1980) (as cited in Doss et al. 2009).
Compiled by: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)
Last Modified: Tuesday, 20 July 2010