| Porzana | |
|---|---|
 | |
| Spotted crake (Porzana porzana) | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Gruiformes |
| Family: | Rallidae |
| Genus: | Porzana Vieillot, 1816 |
| Type species | |
| Rallus porzana Linnaeus, 1766 | |
| Species | |
see text | |
| Synonyms | |
Porzana is a genus of birds in the crake and rail family, Rallidae. Its scientific name is derived from Venetian terms for small rails. [1] The spotted crake (P. porzana) is the type species.
The genus Porzana was erected by the French ornithologist Louis Pierre Vieillot in 1816 with the spotted crake (Porzana porzana) as the type species. [2] The genus unites the typical "crakes" found essentially anywhere in the world except desert and polar regions. It contains 3 living species. In addition, a large number of prehistorically extinct species known only from fossil or subfossil remains have been discovered. The genera Coturnicops , Crex (including Crecopsis) and Laterallus have been suggested to be closely related. [3]
However, molecular phylogenetic analyses have confirmed the suspicion, raised in the late 20th century in the first cladistic studies of morphology, that the "genus" Porzana is rather an evolutionary grade, consisting of an assemblage of unrelated plesiomorphic rails. Micropygia is maintained as monotypic genus for the ocellated crake until its relationships are fully resolved. The ash-throated crake, which was only tentatively placed in Porzana, has been united with the two former species of Neocrex in Mustelirallus ; they are almost certainly closely related to Pardirallus . [3] [4] [5] The white-browed crake, meanwhile, is today usually placed in a monotypic genus Poliolimnas again, as it was by various authors in the past.
The molecular data find Crex part of a more ancient lineage including Gallirallus and Rallus however; this clade (without Crex) is also well supported by the morphological data, so the similarities between Crex and the crakes seem to be due to a convergent anatomy. Coturnicops and Laterallus, meanwhile, seem closely related to each other and at least the dot-winged crake and yellow-breasted crake as well as Anurolimnas , but not to the core group of Porzana. Part of Amaurornis seems to form a complex with the remaining small species of "Porzana"; the old name Zapornia is now re-established for these. Finally, there is Porzana proper, a group of a few fairly large species which seems close to the last common ancestor of coots and moorhens; the spot-flanked gallinule, presently placed in Gallinula or separated in a monotypic Porphyriops, may be a particularly close relative. [4] [5]
These birds are among the smaller members of their family, none being larger than a chicken and some really tiny, smaller than a starling or thrush. Their upperparts are a cryptic lighter or darker brownish hue. The underside is also brown in some, but more often buff or grey. Several species have patterns like whitish dots or black-and-white barred flanks, conspicuous close up, but at a distance providing additional camouflage in these birds' habitat. Some others are rather uniformly blackish-brown all over. The bill and feet are often brightly colored in red to yellow hues; the eyes' iris has some reddish-brownish hue, sometimes being bright red and also very conspicuous at close quarters. Porzana males and females generally differ barely if at all; in the little crake (P. parva), however, they differ so much they might be mistaken for separate species. [6]
Most species of Porzana crakes inhabit wetlands. Some, however, are (or were) found on rocky islands with little water; even these, though, prefer places where abundant vegetation provides a dense ground-cover to hide in. They are usually reclusive and shy, but unlike the larger rails are active and inquisitive birds. When foraging, they will investigate anything that catches their attention and is not considered a predator; in some places, this even includes any humans and their food or equipment that visit these birds' habitat. Their food is mostly small invertebrates – typically arthropods and mollusks – as well as selected plants, seeds and fruit. This is complemented by any small vertebrate they can catch, such as a fish or frog. They can swim if they need to and even dive a bit, but not for extended distances; rather, they prefer to clamber through dense reeds to escape threats, or walk on floating vegetation or just passively drift around a spot when foraging. [6]
As usual for Rallidae, their flight is rather clumsy and their navigation skills and ability to maintain course against the wind are poor; on the other hand, their stamina in the air is exception for their small size; several species migrate thousands of kilometers every spring and autumn, while others originated from wind-blown individuals swept to oceanic islands just as far away from any continent. In this regard, Porzana presently in fact stands supreme among the Rallidae, and even among birds in general it is quite remarkable for its radiation of oceanic island lineages. Gallirallus rivals it in extent, but unlike the cosmopolitan Porzana crakes these rails simply originate in the region next to Oceania and have otherwise not much spread beyond. Porzana species, by contrast, are attested from islands in almost every ocean. As usual for oceanic-island Rallidae, a number of them eventually became flightless due to the rarity of predators on their ocean homes; most of them went extinct from hunting and predation after humans and their accompanying animals reached these islands. [6]
The social and sexual habits of this genus do not markedly differ from the usual standards of their family. They possess the typical complex repertoire of calls, usually quite high-pitched due to the small size (the namesake "crake" calls), but in some situations communicate with a surprisingly deep booming calls. Porzana crakes are monogamous and defend a territory during the breeding season. For the rest of the year, the pairs split and territories are abandoned; pairmates often choose a different partner for the next breeding season. The nest sites are typically in hidden spots at the water's edge, but can be in any dense clump of vegetation between shallow water and dry land as the situation requires. Not much effort is put into building the nest; usually the parents do little more than press down the plants with their bodies. However, the nest cup is carefully lined with soft dry plant material, feathers or hair, which the parents collect specifically for this purpose. The clutch is around 5–10 eggs (a few species have less) whose buffish color is more or less obscured by a rather even and dense cover of brown to purplish dots. The hatchlings are remarkably long-legged and covered blackish down feathers as is typical for rails and crakes. They are precocial and able to leave the nest immediately after recovering from hatching. After a few days they can accompany their parents on long walks, and the nest is soon deserted. After two months or so, the young learn to fly and are able to fend for their own, and have parted ways with their parents. If the pair nests early and/or the clutch fails, they will usually try to raise a second clutch in the same season. [6]
The genus Porzana contains 3 living species. [7]
| Common name | Scientific name and subspecies | Range | Size and ecology | IUCN status and estimated population |
|---|---|---|---|---|
| Spotted crake | Porzana porzana (Linnaeus, 1766) | breeds in Europe and western Asia, winters in Africa and India | Size: Habitat: Diet: | LC |
| Australian crake | Porzana fluminea Gould, 1843 | Australia | Size: Habitat: Diet: | LC |
| Sora | Porzana carolina (Linnaeus, 1758) | breeds in North America, winters around the Caribbean | Size: Habitat: Diet: | LC |
It is to be expected that most or all of these species will be transferred to the genus Zapornia .
By standards of their family, the fossil record of "Porzana" is not very comprehensive and modestly old. The most ancient fossils that were placed here date from about one dozen million years ago during the Astaracian. A few older fossils of extant rail lineages are known, suggesting that older Porzana (or at least Zapornia) fossils may also eventually be found. More importantly, the comparatively abundant remains from around 4 million years ago may indicate that even Porzana proper had its near-cosmopolitan distribution at that time already. The fossils, sorted by age, are:
The Middle Pleistocene fossil described as Porzana auffenbergi is now placed in Rallus .
The Gruiformes are an order containing a considerable number of living and extinct bird families, with a widespread geographical diversity. Gruiform means "crane-like".
Rails are a large, cosmopolitan family of small- to medium-sized terrestrial and/or semi-amphibious birds. The family exhibits considerable diversity in its forms, and includes such ubiquitous species as the crakes, coots, and gallinule; other rail species are extremely rare or endangered. Many are associated with wetland habitats, some being semi-aquatic like waterfowl, but many more are wading birds or shorebirds. The ideal rail habitats are marsh areas, including rice paddies, and flooded fields or open forest. They are especially fond of dense vegetation for nesting. The rail family is found in every terrestrial habitat with the exception of dry desert, polar or freezing regions, and alpine areas. Members of Rallidae occur on every continent except Antarctica. Numerous unique island species are known.
The Inaccessible Island rail is a small bird of the rail family, Rallidae. Endemic to Inaccessible Island in the Tristan Archipelago in the isolated south Atlantic, it is the smallest extant flightless bird in the world. The species was formally described by physician Percy Lowe in 1923 but had first come to the attention of scientists 50 years earlier. The Inaccessible Island rail's taxonomic affinities and origin were a long-standing mystery; in 2018 its closest relative was identified as the South American dot-winged crake, and it was decided that both species are best classified in the genus Laterallus.
The spotted crake is a small waterbird of the family Rallidae. The scientific name is derived from Venetian terms for small rails.
The little crake is a very small waterbird of the family Rallidae. parva is Latin for "small". This species was long included in the genus Porzana.
Baillon's crake, also known as the marsh crake, is a small waterbird of the family Rallidae.
Moorhens—sometimes called marsh hens—are medium-sized water birds that are members of the rail family (Rallidae). Most species are placed in the genus Gallinula, Latin for "little hen". They are close relatives of coots. They are often referred to as (black) gallinules. Recently, one of the species of Gallinula was found to have enough differences to form a new genus Paragallinula with the only species being the lesser moorhen.
The ruddy-breasted crake, or ruddy crake, is a waterbird in the rail and crake family Rallidae.
Flightless birds have, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the common ostrich.
The Galapagos crake, also called the Galapagos rail and Darwin's rail, is a vulnerable species of rail in subfamily Rallinae of family Rallidae, the rails, gallinules, and coots. It is endemic to the Galápagos Islands. It resembles its sister species, the black rail of the Americas, from which it diverged 1.2 million years ago.
Rallus is a genus of wetland birds of the rail family. Sometimes, the genera Lewinia and Gallirallus are included in it. Six of the species are found in the Americas, and the three species found in Eurasia, Africa and Madagascar are very closely related to each other, suggesting they are descended from a single invasion of a New World ancestor.
Laterallus is a genus of birds in the rail family Rallidae. These small, relatively short-billed terrestrial rails are found among dense vegetation near water in the Neotropics, although a single species, the black rail, also occurs in the United States.
The black-banded crake is a species of bird in subfamily Rallinae of family Rallidae, the rails, gallinules, and coots. It is found in Brazil, Colombia, Ecuador, and Peru.
The spotless crake is a species of bird in the rail family, Rallidae. It is widely distributed species occurring from the Philippines, New Guinea and Australia, across the southern Pacific Ocean to the Marquesas Islands and south to New Zealand.
The great Oʻahu rail or great Oʻahu crake is a little-known extinct bird species from Oʻahu, Hawaiʻi, attested only by a few subfossil bones. The holotype is a right tarsometatarsus found in a flooded sinkhole on the ʻEwa Plain near Barbers Point, the southwestern tip of Oʻahu.
The great Maui crake or great Maui rail is an extinct bird species from Maui, Hawaiian Islands, known only from subfossil bones. The holotype are the bones of one almost-complete skeleton, found in Auwahi Cave on the lower southern slope of Haleakalā at 1,145 m AMSL. Its first remains, however, were recovered in 1972 and/or 1974 from lower Waihoi Valley further east and less than half as far uphill.
The Mangaia crake is an extinct species of flightless bird in the rail family, Rallidae. It was described in 1986 from subfossil bones of late Holocene age found in caves on the island of Mangaia, in the southern Cook Islands of East Polynesia. It was placed in the then-loosely circumscribed genus Porzana, but it almost certainly does not belong to Porzana proper as understood in modern times. Rather, it most likely was one of the crakes which are now separated as genus Zapornia. While the species survived for hundreds of years of Polynesian settlement, even despite the establishment of introduced predators, at some point in the last millennium Mangaia suffered an ecosystem collapse with far-reaching consequences, the extinction of "P." rua among them.
Zapornia is a recently revalidated genus of birds in the rail family Rallidae; it was included in Porzana for much of the late 20th century. These smallish to tiny rails are found across most of the world, but are entirely absent from the Americas except as wind-blown stray birds. A number of species, and probably an even larger number of prehistorically extinct ones, are known only from small Pacific islands; several of these lost the ability to fly in the absence of terrestrial predators. They are somewhat less aquatic than Porzana proper, inhabiting the edges of wetlands, reedbelts, but also drier grass- and shrubland and in some cases open forest.
Hypotaenidia is a genus of birds in the family Rallidae. The genus is considered separate by the IOC and IUCN, while The Clements Checklist of Birds of the World / eBird consider the species to be part of Gallirallus. Since the mid-19th century, when these rather terrestrial birds were recognized to form a genus distinct from the decidedly aquatic Rallus, the validity of Hypotaenidia has been disputed.
Media related to Porzana at Wikimedia Commons
