A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in
freshwater ecosystems, although others make no distinction from
seabird
Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
s that inhabit
marine environments. Some water birds (e.g.
wading birds) are more terrestrial while others (e.g.
waterfowls) are more aquatic, and their adaptations will vary depending on their environment. These adaptations include
webbed feet, beaks, and legs adapted to feed in the water, and the ability to dive from the surface or the air to catch prey in water.
The term ''aquatic bird'' is sometimes also used in this context. A related term that has a narrower meaning is
waterfowl. Some
piscivorous birds of prey
Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
, such as
ospreys,
sea eagles,
fish eagles,
fish owls, and
fishing owls, hunt aquatic prey but do not stay in water for long and live predominantly over dry land, and are not considered water birds. The term waterbird is also used in the context of conservation to refer to any birds that inhabit or depend on bodies of water or
wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
areas. Examples of this use include the
Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) and the
Wallnau Waterbird Reserve.
Types
Some examples of water birds are:
*
Seabird
Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
s (marine birds)
**
Penguins (order
Sphenisciformes)
**
Tropicbirds (order
Phaethontiformes)
**
Albatrosses and
petrels (order
Procellariiformes
Procellariiformes is an order (biology), order of seabirds that comprises four family (biology), families: the albatrosses, the Procellariidae, petrels and shearwaters, and two families of storm petrels. Formerly called Tubinares and still call ...
)
**
Pelican
Pelicans (genus ''Pelecanus'') are a genus of large water birds that make up the family Pelecanidae. They are characterized by a long beak and a large throat pouch used for catching prey and draining water from the scooped-up contents before ...
s (family
Pelecanidae
The Pelecanidae is a family of Pelecaniformes, pelecaniform birds within the Pelecani that contains three genera: the extinct ''Eopelecanus'' and ''Miopelecanus'' and the extant ''Pelecanus''.
Pelecanids have existed since the late Eocene (Pria ...
within order
Pelecaniformes)
**
Gannets,
boobies,
cormorants, and
frigatebirds (families
Sulidae,
Phalacrocoracidae, and
Fregatidae
Frigatebirds are a Family (biology), family of seabirds called Fregatidae which are found across all tropical and subtropical oceans. The five extant species are classified in a single genus, ''Fregata''. All have predominantly black plumage, l ...
within order
Suliformes)
**
Gulls,
terns,
skimmers,
skuas,
auk
Auks or alcids are birds of the family Alcidae in the order Charadriiformes. The alcid family includes the Uria, murres, guillemots, Aethia, auklets, puffins, and Brachyramphus, murrelets. The family contains 25 extant or recently extinct speci ...
s, and
phalaropes (families
Laridae,
Stercorariidae, and
Alcidae, plus genus ''
Phalaropus'', within order
Charadriiformes)
*
Heron
Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 75 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genus ''Botaurus'' are referred to as bi ...
s,
egrets,
bitterns,
ibises,
spoonbills,
shoebills, and
hamerkops (the rest of order
Pelecaniformes)
*
Darters and
anhingas (the rest of order
Suliformes)
*
Shorebirds and
waders (the rest of order
Charadriiformes)
*
Duck
Duck is the common name for numerous species of waterfowl in the family (biology), family Anatidae. Ducks are generally smaller and shorter-necked than swans and goose, geese, which are members of the same family. Divided among several subfam ...
s,
geese,
swan
Swans are birds of the genus ''Cygnus'' within the family Anatidae. The swans' closest relatives include the goose, geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe (biology) ...
s,
magpie geese, and
screamers (order
Anseriformes)
*
Grebes (order
Podicipediformes)
*
Loon
Loons (North American English) or divers (British English, British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family (biolog ...
s (order
Gaviiformes)
*
Storks (order
Ciconiiformes)
*
Flamingos (order
Phoenicopteriformes)
*
Cranes,
rails,
crakes,
coots,
moorhens,
finfoots and
limpkins (families
Gruidae,
Rallidae,
eliornithidaeand
Aramidae within order
Gruiformes)
*
Kingfishers (family
Alcedinidae within order
Coraciiformes)
*
Dippers (family
Cinclidae within order
Passeriformes)
*
Sunbitterns (family
Eurypygidae within order
Eurypygiformes)
Evolution
The evolution of waterbirds is often mainly centered around adaptations to improve feeding techniques. This includes legs that are adapted to diving or wading and webbing between the toes. Many of these adaptations are common between different types of waterbirds. For example,
flamingos and ducks share a similar filter-feeding lifestyle, and the
shoebill has a similar structure (
morphology) to many wading birds.
DNA sequence analysis, specifically the
mitochondrial gene sequencing, has been used to classify and differentiate the various aquatic birds. This classification is found by a
relative apparent synapomorphy analysis (RASA) which highlighted certain branches of genes that classified the domestic duck and fowl, for example, as an outgroup. Comparing and understanding these gene patterns allows scientists to classify aquatic birds.
Conservation
Waterbird conservation efforts in the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
are advanced by numerous organizations, including the 700,000 member strong
Ducks Unlimited. Employing such methods as conservation easements and outright purchase, it uses federal and state habitat reimbursements, sponsorships, member fees, major gifts, donations, royalties, and advertisement to raise over $200 million a year. A minimum of 80 percent
of that revenue goes directly toward
habitat conservation.
Ducks Unlimited partners with a wide range of corporations, governments, other non-governmental organizations, landowners, and private citizens to restore and manage areas that have been degraded and to prevent further degradation of existing wetlands. DU is also active in working with others to recommend government policies that will influence wetlands and the environment. Through March 2021, Ducks Unlimited had conserved at least 15 million acres of waterfowl habitat in North America.
To promote the conservation of waterbirds in America, the United States
Fish and Wildlife Service established the Waterbird Conservation for the Americas to facilitate this over such a large area. The purpose of this initiative is to promote international cooperation and partnership to preserve waterbird habitats, create long term sustainability plans, implement specific conservation plans for regions, and support legal action for waterbird conservation on the regional and national levels.
A 2018 global study analyzing population trends of 461 waterbird species across multiple continents found that ineffective governance strongly predicts population declines, especially in regions like
Central Asia
Central Asia is a region of Asia consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. The countries as a group are also colloquially referred to as the "-stans" as all have names ending with the Persian language, Pers ...
,
Sub-Saharan Africa
Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...
, and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
. The study emphasized that effective governance is a critical factor for successful waterbird conservation.
Extinction

The loss of
wetlands
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
has impacted waterbirds and is driving their extinction in regions where wetlands are polluted. Specifically, in
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
, 33% of wetlands were lost between 1978 and 2008, which is the primary breeding ground for China's waterbird species such as the
Baer's pochard, which is now at risk for extinction. The Baer's pochard's population has decreased to between 150 and 700 birds in recent years due to negative environmental impacts on their habitat as well as human activities such as hunting and fishing.
This loss of wetlands is a result of various sources in China. The rise of urbanization and industries has resulted in pollution and waste in the water. In addition, reclamation projects for construction further threaten ruining the habitats of these birds. For example, the largest of these reclamation projects is the Oufei Project, which spans 8854 hectares.
Interspecific competition

Experimental evidence of competition has been difficult to obtain in highly mobile animals that cannot be meaningfully confined to plots of limited size. Many such animals are believed to compete with less mobile, resident taxa, but the supporting evidence has often remained circumstantial.
One example is the interaction between water birds and
benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...
feeding fish,
or fish that feed at the lowest level of a body of water. Many migratory water birds use similar food resources on their breeding, molting, or overwintering grounds as do resident fish species. Studies, such as that done by Eadie and Keast in 1982, found an inverse relationship between the Goldeneye (duck), goldeneye (a water bird) and benthic feeding fish across multiple lakes.
Mobile water birds tend to avoid areas where their food density is high because this increases competition for resources. When there is abundant food in an area, there are more birds trying to eat it. This can lead to aggression and fighting, as well as a decrease in the overall fitness of the bird.
By avoiding areas of high food density, mobile waterfowl can reduce competition and improve their chances of survival. They can spread out and forage in less crowded areas, which allows them to avoid conflict and obtain the nutrients they need.
Diseases
Outbreaks of diseases spread by waterbirds result from the transition of water-borne viruses to those wild birds. The spread can be caused by dead waterbirds in the vicinity of other organisms, or simply from waterbirds with the virus settling into more densely populated areas (whether by humans or other organisms).
Duck enteritis virus (DEV)
Duck plague (DP), also called duck enteritis virus (DEV), presents the most important concern in mass waterfowl production. Free-ranging water birds are the most likely infectious carriers. While the overall epidemiology of DEV is unknown in western Europe, studies conducted in Poland agree with the high levels of transmission between free-ranging water birds.
DEV is an aetiological agent of DP, which represents one of the most acute and lethal diseases of waterbirds, and infection can spread easily between farmed and wild waterbirds. Over 48 species of birds, including those not considered waterbirds, are susceptible to infection by DEV, and the mortality rate of this disease can reach up to 100%, especially in young birds.
H5N1
Avian influenza caused by infection with Influenza A virus subtype H5N1, H5N1, a highly pathogenic avian influenza virus (HPAIV), has spread in poultry in more than 60 countries in Eurasia and Africa since 1996, when the first outbreak occurred at a goose farm in the Guangdong province in China.
H5N1 in wild birds have spread to Asia, Europe, and Africa, and it is possible for the H5N1 virus to be spread by migratory water birds to the west and south, as genetically closely related H5N1 viruses have been isolated in several countries since 2005.
H5N1 HPAIV infections have become endemic in several countries and cause accidental transmissions to humans. H5N1 viruses are thus now recognized as one of the most likely candidates for the next pandemic.
References
{{Authority control
Aquatic birds,
Birds by common name