Waterfowl

Waterfowl in the United States includes all types of geese, ducks, and swans, as well as a few unrelated aquatic birds including grebes, coots, and loons. In Britain, the term is known only to domesticated geese, swans, and ducks kept for ornamental purposes. The word "wildfowl" refers to this category of wild birds, particularly when used in the context of sport shooting.

Anatidae

The Anatidae are described as the biological family of waterbirds or the waterfowl birds, which includes geese, ducks, and swans. This family has a cosmopolitan distribution, taking place on all the continents of the world. These birds are adapted for swimming and floating on the water surface, and in a few cases, diving in at least shallow water. The family has around 174 species in 43 genera. (The magpie goose is no longer considered to be the part of Anatidae, and now, it is placed in its own family, Anseranatidae)

Generally, they are monogamous and are herbivorous breeders. Numerous species undertake annual migrations. Some species have been domesticated for agriculture, and several others are hunted for recreation and food. Since 1600, five species have become extinct, and several more are threatened with extinction.

Breeding

Generally, Anatidae are monogamous and seasonal breeders. The level of monogamy differs within the family; several of the smaller ducks only maintain the bond for a single season and finds a new partner the following year; on the other side, the larger swans, geese, and a few of the more territorial ducks maintain pair bonds over many years, and even for life in some species. However, forced extra-pair copulation among the anatids is common, taking place in 55 species in 17 genera.

Anatidae is the large proportion of the 3 percent of bird species to possess the penis, though they differ significantly in shape, size, and surface elaboration. Most of the species are adapted for copulation only on the water. They construct simple nests from whatever the available material is close at hand, often lining them with the layer of down plucked from the breast of mother.

In most of the species, only females incubate the eggs. The young are given as precocial, and they are able to feed themselves from birth. One aberrant species, is the black-headed duck, is an obligate brood parasite that laying its eggs in the nests of coots and gulls. While this particular species never raises its young, other numerous ducks lay eggs occasionally in the conspecific nests (members of the same species) in addition to raising their broods.

About Waterfowl

Waterfowl are birds, which are strong swimmers having webbed feet and waterproof feathers. They propel themselves through the water by using their webbed feet like flippers. Geese, Ducks, and swans are given as waterfowl. Several waterfowl spend most of their time on lakes and ponds. A few kinds swim in the sea near the coastlines. Some others, like most geese, live primarily on grassland.

Many kinds of waterfowl are vegetarian, grazing on grass or water weeds, but a few hunt for snails, fish, or insects. Several ducks "dabble," or up-end at the surface of the water with their heads immersed, to eat the undersea food. Other ducks go right beneath the surface to feed at great depths. Furthermore, many ducks fly well and migrate across long distances between their summer breeding sites and the places where they used to spend the winter.

Relationship with Humans

Eider, duck, and goose feathers and down contain long been popular for pillows, bedspreads, coats, and sleeping bags. Also, the members of this family have long been used for food.

Humans have had a very long relationship with geese, ducks, and swans; they are essential culturally and economically to humans, and many duck species have benefited from the association with people. However, some Anatidae are damaging the agricultural pests and have acted as vectors for zoonoses like avian influenza.

Since 1600, 5 species of the ducks have become extinct because of the activities of humans, and the subfossil remains have exhibited that humans caused a number of extinctions in prehistory. Nowadays, several more are considered threatened. Most prehistoric and historic extinctions were insular species, which are vulnerable because of the small populations (often endemic to a single island), and the island tameness.

Evolving on islands, which lacked predators, these species lost antipredator behaviours and the ability to fly as well and were vulnerable to the human-introduced species and hunting pressure. The other declines and extinctions are attributable to overhunting, modification and habitat loss, and hybridization with the introduced ducks (for instance, in Europe, the introduced ruddy duck swamping the white-headed duck). Many governments, conservation, and hunting organisations have made some considerable progress in protecting the ducks and their populations through the creation and habitat protection, protection and laws, and captive-breeding programs.

Description

The geese, ducks, and swans are said to be the small- to large-sized birds having an elongated and broad general body plan, which are also called waterfowl birds. In being rounder, the diving species differ from this. Extant species, which range in size from the cotton pygmy goose, at as small as 26.5 cm and 164 g, to trumpeter swan, at as high as 183 cm and 17.2 kg. The wings are pointed and short and supported by the strong wing muscles, which generate rapid beats in flight. Typically, they have long necks, although this differs in degree between the species.

Systematics

William Elford Leach, an English zoologist, coined the name Anatidae to describe the duck family. It was first mentioned in a guide to the British Museum's contents published in 1820. While the status of the Anatidae is straightforward as a family, and which species properly belong to it is little debated, the relationships of the multiple tribes and subfamilies within it are poorly understood.

The Anatidae’s systematics is in a state of flux. The Anatidae were previously classified into six subfamilies, but an analysis of anatomical characters by Livezey indicates that the nine subfamilies are much better handled. In the late 1980s to 1990s, this classification was popular. But mtDNA sequence analyses, for example, indicate the dabbling and diving ducks do not belong in a similar subfamily.

While shortcomings certainly take place in the analysis of Livezey, mtDNA is some unreliable source for the phylogenetic information in several waterfowl (especially the dabbling ducks) because of their ability to form fertile hybrids, in some rare cases possibly even beyond the genus level (for example, "Barbary duck"). Because the sample size of several molecular studies available to date is smaller, the mtDNA results should be considered with caution.

While still, Anatidae's comprehensive review that unites all evidence into a robust phylogeny is lacking, the confusing data reasons are at least clear: As demonstrated by Late Cretaceous fossil Vegavis named iaai — an early modern waterbird - belonged to an extinct lineage, which is the Anatidae are the ancient group among the modern birds.

Though their earliest direct ancestors are not documented by the fossils yet, likewise may be assumed to have been contemporaries with dinosaurs. The longer period of the evolution, including the shifts from one type of waterbird lifestyle to the other, have obscured several plesiomorphies, while the apomorphies are quite apparently often the result of parallel evolution, for example, the "non-diving duck" type displayed by such unrelated genera as Amazonetta, Dendrocygna, and Cairina.

In an alternate way, the Anatidae can be considered to consist of 3 subfamilies (geese, and swans, ducks, essentially) that contain the groups, which are presented here as tribes, having the swans separated as subfamily Cygninae, which is the goose subfamily anserinae also having the whistling ducks, and the Anatidae consisting all other clades.

Genera

For both the recent and living extinct members of every genus, we can refer to the Anatidae species.

1. Subfamily: Dendrocygninae is a phylum of the Dendrocygnina (one of the pantropical genus, of distinctive long-legged goose-like birds)

• Thalassornis, white-backed duck

• Dendrocygna, whistling ducks waterfowl (8 living species)

2. Subfamily: Swans, anserinae, and geese (ranging from 3–7 extant genera having 25–30 living species, primarily cool temperate Northern Hemisphere, but also a few Southern Hemisphere species, with the swans present in one genus [two genera in a few treatments], and the geese present in three genera [two genera in a few treatments]. Sometimes, Some other species are placed herein, but somewhat seem more distinct)

• Anser, grey geese, and white geese (11 species)

• Cygnus, true swans (6 species, where 4 are sometimes separated in Olor)

• Branta, black geese (6 living species)

3. Subfamily: Aythyinae, which are the diving ducks (A few 15 species of the diving ducks, of worldwide distribution, either in two to four genera; the 1986 morphological analysis has suggested that possibly extinct Indian pink-headed duck, previously treated separately in the Rhodonessa location, should now be placed in Netta. This, however, has been called into question. Moreover, while morphologically close to the dabbling ducks, the mtDNA data indicate a treatment as a distinct subfamily is correct, with the Tadorninae being closer to the dabbling ducks compared to the diving ducks waterfowl)

• Aythya, pochards, scaups, etc. (12 species)

• Netta, red-crested pochard and allies (4 species, and out of that, 1 probably extinct)

4. Subfamily: Anatinae, the moa-nalos, and dabbling ducks (The dabbling duck group, of the worldwide distribution, were restricted previously to either one or two genera, but they had been extended to include 8 extant genera and around 55 living species, including many genera formerly called the "perching ducks" mtDNA on the other side, confirms that the genus Anas as over-lumped and also casts doubt on the diving duck affiliations of many genera. The moa-nalos, where 4 species in 3 genera are well-known to date, are a peculiar group of the flightless, extinct anatids from the Islands of Hawaiian. Gigantic with massive bills and in size, they were believed to be geese but have been exhibited to be actually closely related to the mallards. They also evolved, filling the ecological niche of ungulates, turtles, including other megaherbivores.

• Chendytes, diving-geese (which is a basal member of dabbling duck clade)

• Anas: mallards, pintails, and more (40–50 living species and 3 extinct)

Fossil Anatidae

Anatids' fossil record is extensive, but several prehistoric genera may not be unequivocally assigned to the present-day subfamilies for some reasons. For prehistoric species of the extant genera, one can refer to the respective genus accounts.

Dendrocheninae – it is a more advanced relative of either whistling-ducks or an ancestral relative of the stiff tailed ducks, which are paralleling whistling-ducks; if not extinct, possibly belong in the Oxyurinae (with Malacorhynchus)

• Manuherikia (Bathans Early or Middle Miocene of the Otago, New Zealand)

• Dendrochen (which is the Early – Late? Miocene) – includes "A." oligocaena, "Anas" Integra