Porphyrio Poliocephalus – The Grey-Headed Swamphen
Related to Florida’s native Common Gallinule, Purple Gallinule, and American Coot, the bigger, bulkier Swamphen looks superficially like a Purple Gallinule on massive doses of steroids. The Swamphen is an Old World species and is a relatively recent newcomer to Florida’s wetlands, being first recorded in Pembroke Pines, Florida in 1996, having likely escaped or been released from a private bird collection.
Even with early aggressive control efforts, the Swamphen’s population exploded and it is now a common sight across much of south Florida where it competes with native gallinules, Least Bitterns and other imperiled wetland birds for habitat and resources. The full impact of this big exotic bird is being intensively studied and is still not fully understood.
The Grey-Headed Swamphen vs Purple Swamphen
Six races/species of swamphen range from Australia, through Asia and the Middle East into Africa and southern Europe. Once all lumped together under the moniker of “Purple Swamphen”, it is believed that the majority of swamphens in Florida represent what is now known as the Grey-headed Swamphen (P. poliocephalus), which occurs naturally from the Middle East and the Indian subcontinent to southern China and northern Thailand.
Some Florida birds seem to sport vibrant dark blue heads, more representative of Western Swamphen (P. porphyrio) from southwest Europe and northwest Africa (or another blue-headed species/subspecies), and perhaps the genes of more than one race are represented in the Florida population.
What is the Diet of a Grey-Headed Swamphen?
Feeding mostly on the shoots and stems of wetland plants, Swamphens are not opposed to snacking on the occasional small fish, snail, frog, and the eggs and young of other birds. With their long red toes acting like snowshoes to distribute their weight, Swamphens easily tramp across floating wetland plants.
They may also occasionally be seen swimming or more often, flying low and clumsily over the marsh with their long, gangly legs dangling below.
The Habitat of a Grey-Headed Swamphen in Florida
Despite their unusual appearance, Swamphens have shown a tenacity for surviving and succeeding in Florida’s wetlands and it seems they are here to stay. As just one of many hundreds of introduced exotic wildlife species in the Everglades, it remains to be seen what the long-term repercussions of the Swamphen’s presence will be on our wetlands and the native wildlife that call south Florida.
How Does the Grey-Headed Swamphen Breed?
In their native Asia, Grey-Headed Swamphens tend to breed seasonally, but the season varies and correlates with peak rainfall in the region, usually in the summer. In Florida, most likely due to the mild temperatures, Gray-Headed Swamphens breed year-round. Their chicks have been observed during all months of the year, with the exclusion of June, September, November, and December.
In captivity, they produce two clutches a year. They prefer warm reed beds and build their nest out of a mound of vegetation above the waterline.
The male puts on an elaborate courtship display, as he holds water weeds in his bill and bows to the female with loud chuckles. They tend toward monogamy but also work in cooperative breeding groups made up of multiple males and females sharing a nest.
How Many Eggs Can The Grey-Headed Swamphen Lay?
Each clutch contains 2-7 eggs. The nest can hold up to 12 eggs. The eggs are white or pale buff with random markings of brown or gray splotches. Both sexes incubate the eggs, sitting on them for about 24 days to three weeks. The chicks are fed by the adults initially, but begin to find food on their own a few days after hatching, with adults providing supplemental feed for several weeks. The chicks reach sexual maturity at about 1-2 years.
Do Grey-Headed Swamphen’s Migrate?
The Grey-Headed Swamphen is a non-migratory bird that appears to enjoy the good life it has found in South Florida’s sunny freshwater marshes. They have, however, expanded their range. By 2011, they had been spotted in 30 different places in Florida, and as far north as Georgia, approximately 423 miles from Pembroke Pines.
As they move into colder climates, they may become migratory in response to the lower temperatures. In their native range in Asia, the Grey-Headed Swamphen is generally not migratory but do disperse hundreds of miles as a response to changes in local water levels.
Interestingly, the Purple Swamphen is native to American Samoa, Gaum, and Baker and Howland Islands, and the Commonwealth of the Mariana Islands, all U.S. territories.