THE WORLD BIRDS - An Online Bird Book
WATERFOWL - Swans and Geese
The term waterfowl is used to describe any member of the order Anseriformes. A series of articles describes all the waterfowl. This specific article describes the
"swans and geese" which belong to family Anatidae, subfamily Anserinae.
Anseriformes
Most species of the order Anseriformes spend a considerable amount of time in water. In fact, they are called waterfowls. Their webbed feet make for efficient swimming. A few species spend little time in water and thus their feet are only partially webbed. Most waterfowl are also good flyers, many migrating long distances to escape the cold and others migrating shorter distances for optimizing their food supply. All species, except the screamers, have a wide and relatively flat bill. The shape of a species bill and also their tongue is a function of their diet. Considering the entire order, they eat aquatic plants, grasses, sedges, algae, plankton, insects, insect larvae, mollusks, crustaceans, fish, fruits, grains, rice. Most species are monogamous and if they lose a partner seem to mourn. Males are larger and heavier than females. The chicks are well developed when they hatch and can walk almost immediately.
The order
Anseriformes has 3 familes: Anatidae, Anhimidae, Anseranatidae. Family Anatidae is comprised of the ducks, swans, and geese which amounts to about 160 species. Family
Anhimidae is made up of 3 screamer species while family
Anseranatidae has only one species, the magpie goose. Since these latter two families contain so few species, it seems appropriate to consider the entire order in this series of articles.
Anatidae
The Anatidae family has the following subfamiles:
Anatinae: dabbling ducks and
teals
Anserinae: geese, swans
Aythyinae: diving ducks
Dendrocygninae: whistling ducks
Merginae: sea-ducks
Oxyurinae: stiff-tailed ducks
Plectropterinae: spur-winged goose
Stictonettinae: freckled duck
Tadorninae: shelducks, shelgeese
Swans and Geese
Swans
Swans are the largest waterfowl, substantially larger than the other members of their subfamily, geese.They wingspans are over 3 m (10 ft). Hundreds of years ago they used to be considered a luxury food reserved for royalty; it was then taboo for commoners to hunt swan. In the present day that feeling of taboo is renforced by their beauty and their perceived scacity. "Perceived" scarity because in some places the swan population has increased to the point where they are pests. While it may seem logical to allow swan hunting in such cases, most national or local govermentss still protect swans.
The sexes are alike in appearance, but the males are larger. Most swans mate for life, their divorce rate is only about 3%. When it is time to procreate, they have a courtship behavior where they nod their heads towards each other while shaking their wings. The males help with nest construction and also with incubation of the eggs. Perhaps because the sexes share household duties that helps explain their low divorce rate. Swans molt in the summer and then are unable to fly for about 6 weeks. Not flying at that time is not very inconvenient as they are raising the young and there is still plenty of time before migration season.
Swans fly with their necks extended and they often a V-shapes as is true for geese. The reason some flocks fly in V-shape has to do with aerodynamics. The leader has more air resistance, thus helping the ones behind it. After a white, the lead position rotates and someone else has to push the air aside. A V-shaped formation is especially important for large birdes. Pelicans also frequently travel this way.
Swans live in temperate climates. Many breed in the arctic when it is relatively warm, but leave for warmer climates when the juveniles are able to fly. Swans often forage on water.
They eat roots, tubers, stems and leaves of aquatic and submerged plants.With their long necks much vegetation is usually within reach. And that reach can be extended if the go "bottoms up" and dabble like a duck. Swans also forage in fields paying special attention to the dregs of crops in winter fields. In addition to plants, some swans eat insects, mollusks, and crustaceans.
The Coscoroba Swan belongs to its own genus Coscoroba. It is considered as an early branch from the common ancestor leading to true geese and swans.
Geese
Geese are large waterfowl, larger than ducks and smaller than swans. They are amount the earliest animals that were domesticated, at least 3000 year ago in Egypt. and perhaps sooner. The early domestication must have been aided by geese imprinting on its caregiver at birth. Thus the new goosling would treat their handler
as a parent and not try to escape or bite the hand that fed it. Another benefit of a domesicated goose is that the honk when there is an intruder, whether that be a fox or a human intruder, and will try to drive it off.
Like the swans, geese fly in V's because it saves energy. They honk frequently while flying probably to encourage the flock to stay together and in formation, akin to a coxman in racing shell. The honking also serves to attrack other geese to their journey. That honking also alerts hunters and. of course, can be detrimental to the health of a goose, but the larger the skein (yes, skein refers to a flock on flying geese, not just a coil of yarn) the lower the odds of getting shot for any individual goose. Other geese related words: a gaggle is a group of geese on the ground; a gander is a male goose; and a goosling is a young geese.
Some other ways that geese are similar to swan's:
Male larger than female
When they moult they cannot fly; then like to be near water for protection from predators.
Monogomous - usually stay with the same partner for life.
Many migrate long distances.
Fly with next outstretched, rest with the neck in an S shape.
The sexes are dimorphic in appearance. This is yet another way that geese are similar to swans. But the geese have an exception - the three species in genus Nettapus, the pygmy geese, are dimorphic. Their nearest relatives are unclear, and they may not rightfully belong ot the swan and goose subfamily Anserinae. This lack of dimorphism is one reason why. The extreme size difference between true geese and pygmy geese is another.
Most geese species are mainly vegetarians. Many will dabble for aquatic food, but even the species that graze mainly on the land prefer to live close to water for protection as all geese are excellent swimmers. Taken as a whole, gease will eat aquatic vegetation, algae, grasses, sedges and kelp. Some specices will eat insects, small fish, and crustaceans. In the winter time when greens are harder to find most geese will the dregs of crop fields such as corn and other grains, rice, beans, and even potatioes.
The cape barren goose belongs to its own genus Cereopsis. It It may belong to the goose and swan subfamily Anserinae or to the shelduck subfamily Tadorninae. The freckled duck, Stictonetta naevosa, has been assigned to its own subfamily Stictonettinae. It is thought to be closest to the cape barren goose. The spur-winged goose belongs to its own genus Cereopsis and own subfamily Plectropterinae. The magpie goose, Anseranas semipalmata, does not belong to the swan and goose subfamily Anserinae. Stranger still it does not belong to the family Anatidae; it is alone in its own family Anseranatidae.
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The Swans
Genus Coscoroba - 1 species
Swan, Coscoroba Coscoroba coscoroba
Image by: 1,
2) Dick Daniels -
Sylvan Heights 3) Dick - San Diego Zoo 4) Nick Athanas - Chile
Genus Cygnus
Swan, Bewick's Cygnus bewickii
Image by: 1,
2) Dick Daniels -
Sylvan Heights 3)
Alpsdake - Japan 4)
Maga-chan - Japan
Swan, Black Cygnus atratus
Image by: 1)
Oystercatcher 2)
Dick Daniels - Pine Grove Waterfowl Park, Virginia 3)
Dick - Australia 4)
birdsaspoetry Video by
Avibirds.
Swan, Black-necked Cygnus melancoryphus
Image by: 1)
Sandy Cole -
Sylvan Heights 2, 3) Dick Daniels -
Sylvan Heights
Swam, Mute Cygnus olor
Image by: 1
) Dick - Scotland 2) Dick -
Flamingo Gardens - Flroida
3, 4) Dick - New Jersey
Video by
Avibirds.
Swan, Trumpeter Cygnus buccinator
Image by:
1) Dick Daniels - Wyoming 2) Dick - Anchorage Zoo, Alaska 3)
Dick - Wyoming 4)
US Army Corps of Engineers
1) Juvenile
Swan, Whistling Cygnus columbianus
Image by:
1, 3) Dick Daniels - Pine Grove Waterfowl Park, Virginia 2)
Matthew_Beziat - Maryland
Swan,_Whooper Cygnus cygnus
Image by: 1) Margrit
2)
Dick Daniels - Jacksonville Zoo in Florida 3)
Harald_Henkel 4) Alan_Shearman
Video by
Avibirds.
The Geese
Anser and Branta are the two genera that comprise the
true geese. The Cape Barren goose, spur-winged goose, and magpie goose are not true geese. Similarly, many species termed goose actually belong to the shelduck subfamily. The closest relatives of the true geese are the swans of genus
cygnus.
Many geese species spend most of their tme on land. But they often retreat to water if they feel threated. With their webbed feet thet are excellent swimmers.
Genus Anser
The "grey" geese of genus Anser are closely related to the "black" geese in genus Branta. Anser geese have pink or orange legs and feet;
Branta geese have black or dark-grey legs and feet. Also the typical Branta goose has more black on its head and neck than does the typical Anser goose. The "white geese" are a small group of waterfowl which used to be placed in genus
Chen, but are now placed in Anser. They breed on subarctic areas of North America and around the Bering Strait, migrating south in winter.
Goose,_Bar-headed Anser indicus
Image by:
1, 2) Dick Daniels-
Sylvan
Heights 3)
Diliff 4)
Imran Shah Video by
Avibirds.
Goose,_Chinese
Image by: 1 - 3) Dick Daniels - the Central Zoo in Nepal 4) Dick - Ranomafana, Madagascar
Video by
Avibirds.
The dark versions below might be swan geese.
Goose,_Emperor Anser canagica
Image by: 1)
USFWS 2)
Tim Bowman USFWS
3, 5, 6) Dick Daniels -
Sylvan Heights 4)
Sandy Cole -
Sylvan Heights
1) Head stained oranged from iron-rich water.
Goose,_Greater White-fronted Anser albifrons
Image by:
1, 2) Alan Vernon 3) Dick Daniels -
Sylvan Heights 4)
LonelyShrimp Video by
Avibirds.
Goose,_Greylag Anser anser
Image by: 1)
Alan D Wilson - Washington 2) Dick Daniels - England 3)
Colin_Frankland 4) I
mran Shah - Pakistan
Video by
Avibirds.
6) Greylag / Domestic Goose hybrid
Goose,_Lesser White-fronted Anser erythropus
Image by: 1)
distillated - England 2)
BS Thurner Hof 3)
Tilly Mint - Wales
4)
LHG Creative Photography - England
Goose,_Pink-footed Anser brachyrhynchus
Image by: 1)
Scyrene Magnus_Lindberg 2)
Magnus_Lindberg 3
) MPF - Northumberland, UK
Goose,_Ross's Anser rossii
Image by: 1)
Andrew C - Ohio
2) Mike Baird 3, 4)
Dick Daniels -
Sylvan Heights 5)
Bill Bouton - California 6)
Len Blumin - California
4) Dark morph
Goose,_Snow Anser caerulescens
Image by: 1) Dick Daniels - North Carolina 2) Dick -
Sylvan Heights 3) Alan D Wilson 4)
Edwin Forsythe
Goose,_Swan Anser cygnoides
Image by: 1)
Heather Paul 2) Dick Daniels - the Central Zoo in Nepal 3)
LonelyShrimp 4)
Goose,_Taiga Bean Anser fabalis
Image by: 1)
MPF 2)
Marton_Berntsen - Norway 3)
Adrian_Pingstone
Goose,_Tundra Bean Anser serrirostris
Image by: 1)
Arne List 2)
Hiyashi Haka 3)
Radovan_Vaclav - Slovakia
Genus Branta
The Branta geese can be distinguished from other geese by their legs and feet, which are black or very dark grey. Furthermore, they have black bills and large areas of black on the head and neck.
Brant Branta bernicla
Image by: 1) Alan D Wilson - British Columbia
2) Dick Daniels -
Sylvan Heights 3) Elaine Wilson - British Columbia 4)
Cristiano Crolle - Texel, Holland
Goose,_Barnacle Branta leucopsis
Image by: 1)
Sandy Cole -
Birds of Eden, South Africa 2)
Dick Daniels -
Birds of
Eden 3) Mibby23 4)
Harold_Olsen_NTSU
Goose,_Cackling Branta hutchinsii
Image by:
1) Tim Bowman, USFWS
2)
Alan Vernon - California 3)
VJAnderson - Washington state 4)
Doak - Minnesota
4) Canada goose and cackling goose
Goose,_Canada Branta canadensis
Image by: 1) Dick Daniels - New Hampshire
2) Dick - North Carolina 3)
Dick - New Jersey 4) Dick - New York
Nene Branta sandvicensis
Image by:
1, 2) Dick Daniels - Kauai, Hawaii 3)
Zabdiel - England 4) Dick - Sylvan Heights
4) The Nene has a partially webbed foot.
Goose,_Red-breasted Branta ruficollis
Image by:
1, 3) Dick Daniels -
Sylvan Heights 2)
Sandy Cole -
Sylvan Heights 5)
Video by
Avibirds.
Genus Cereopsis
- 1 species
The cape barren goose belongs to its own genus Cereopsis. It It may belong to swan and goose subfamily
Anserinae or to the shelduck subfamily Tadorninae. It will be treated here as part of Anserinae.
Goose,_Cape Barren Cereopsis novaehollandiae
Image by: 1)
JJ Harrison 2)
Dick Daniels -
Sylvan Heights 3)
Dick - Australia 4)
Ed_Dunens Video by
Avibirds
Genus Nettapus
The Pygmy geese are a group of very small "perching ducks" in the genus
Nettapus which breed in the Old World tropics. They are the smallest of all waterfowl. There nearest relatives are unclear. They are grouped here with the swan and goose subfamily Anserinae mainly because of "goose" being part of their name. They are probably closer to the dabblng ducks of subfamily Anatinae, but even that relationship is distant. That said, they do feed by dabbling.
Goose,_African Pygmy Nettapus auritus
Image by: 1)
Dick Daniels - San Diego Zoo
2, 3) Dick Daniels -
the
North Carolina Zoo 4) Dick -
Sylvan Heights
1) Pair (female on left) 2) Female 3, 4) Male
Goose,_Cotton Pygmy Nettapus coromandelianus
Image by: 1)
JJ Harrison - Thailand 2)
JM Garg 3)
Phadke09 4)
Mprasannak
1 - 3) Female 4 - 7) Male
Goose,_Green Pygmy Nettapus pulchellus
Image by: 1)
Kazredracer 2)
_David_Cook - Northern Territory 3) )
Dick Daniels -
Sylvan Heights 4)
Summerdrought
1, 2) Female 3, 4) Male
Genus Plectropterus - 1 species
The Spur-winged Goose is related to the geese and the shelducks, but distinct from both of these in a number of anatomical features, and therefore placed in its own subfamily, the Plectropterinae.
Goose,_Spur-winged Plectropterus gambensis
Image by:
1, 2, 3, 7, 8) Dick Daniels -
Sylvan Heights 4) Charlie Wseterinrn - Botswana
5, 6) Dick - near De Hoop Nature Reserve, South Africa 5)
Dick - near De Hoop
1, 2, 3, 4)
Northern Spur-winged Goose (
P. g. gambensis) 5 -8)
Black Spur-winged Goose (
P. g. niger)
Family Anatidae, Subfamily Stictonettinae - Freckled Duck
The only member of this subfamily is the freckled duck, it roots may predate the duck subfamily. It is thought to be closest to the cape barren goose.
Genus Stictonetta - 1 species
Duck,_Freckled Stictonetta naevosa
Image by: 1)
Sandy Cole -
Sylvan Heights 2, 3, 4) Dick -
Sylvan Heights
1) Chick 2, 3) Female 4) Male