Mute swan (Cygnus olor): Elegance, aggression, and adaptation

The mute swan (Cygnus olor) is a large waterbird native to much of Europe and parts of western Asia, and has also been introduced to North America, southern Africa, and New Zealand. Despite its name, the mute swan is not truly silent but is less vocal than other swan species. It is among the heaviest flying birds and is notable for its long, curved neck, white plumage, and distinctive orange bill. Closely associated with freshwater habitats, the species is well known for its territorial behavior and enduring pair bonds. While revered in many European cultures as a symbol of grace and fidelity, the mute swan’s ecological impact, especially in introduced regions, continues to be the subject of active research and management.

Discovery

The mute swan has been present in European ecosystems since at least the late Pleistocene, with archaeological evidence indicating its long association with post-glacial habitats. Subfossil remains dated to approximately 6,000 years before present have been recovered from peat deposits in East Anglia, while older occurrences (up to 13,000 years BP) are recorded from sites in France. Additional finds extend its prehistoric range from Ireland to Portugal and Italy. These remains confirm that the species has occupied temperate regions of western Eurasia for millennia and was likely familiar to early human populations, although no specific historical observer is credited with its first recognition.

The species was formally described in 1789 by German naturalist Johann Friedrich Gmelin, who classified it under the genus Anas, naming it Anas olor. The specific epithet olor is derived from Latin, meaning “swan.” In 1803, Johann Matthäus Bechstein reassigned the species to a newly established genus, Cygnus, based on morphological distinctions from ducks and geese. The current binomial, Cygnus olor, reflects this taxonomic revision. The name Cygnus originates from a variant of the Greek word kyknos, also meaning “swan,” illustrating the continuity of linguistic and cultural associations across time.

Phylogenetic studies indicate that Cygnus olor, despite its Palearctic distribution, is more closely related to the black swan (Cygnus atratus) of Australia and the black-necked swan (Cygnus melancoryphus) of South America than to other Northern Hemisphere species within the genus. It is a monotypic species, with no extant subspecies recognized.

The fossil record includes both extinct relatives and paleosubspecies. Cygnus olor bergmanni, a large-bodied form known from Azerbaijan, appears to differ only in size from the living bird. A more distantly related extinct species, Cygnus falconeri, inhabited Malta and Sicily during the Middle Pleistocene and is notable for its large size and flightlessness. Fossils attributed to mute-type swans, including Cygnus paloregonus, have also been discovered in North America, spanning from the Miocene to the late Pleistocene. These findings suggest a broader prehistoric distribution of ancestral swan lineages related to Cygnus olor.

Identification

The mute swan is a large-bodied waterfowl species notable for its considerable mass and wingspan. It typically ranks as the second largest swan species by average body size, after the trumpeter swan (Cygnus buccinator), although large males may reach or exceed the trumpeter swan in mass. Adult mute swans generally measure between 140 and 160 centimeters (4.6-5.2 feet) in body length, with recorded extremes ranging from 125 to 170 centimeters (4.1-5.6 feet). The wingspan ranges from 200 to 240 centimeters (6.6-7.9 feet).

Average body mass differs between sexes: males typically weigh 10.6 to 11.9 kilograms (23.4-26.2 pounds), with a documented range of 9.2 to 15 kilograms (20.3-33 pounds); females are smaller, averaging 8.5 to 9.7 kilograms (18.7-21.4 pounds). An unusually large male from Poland weighed approximately 23 kilograms (50.7 pounds), possibly representing the highest verified weight for any flying bird, although whether the individual was still capable of flight is uncertain. In level flight, mute swans can reach speeds up to 88.5 kmh (55 mph), and during takeoff, they may run along the water’s surface at approximately 48 kmh (30 mph) to gain lift.

The species exhibits moderate sexual dimorphism. Males are generally larger, with thicker necks and a more pronounced black basal knob on the upper mandible. Females show more slender proportions, and the knob is reduced in size. Adult plumage is entirely white, although the feathers, particularly on the head and neck, are often stained orange-brown due to iron and tannins present in some water bodies. The bill is bright orange with a black nail and black base surrounding the nostrils. The legs and feet are uniformly dark grey.

Juvenile birds, or cygnets, differ noticeably in appearance. Their down may be grey, buff, or white, with grey and buff morphs being most common. White cygnets carry a leucistic gene but are not albino. Their bills remain dull grey-black for the first year. Cygnets grow rapidly and typically reach near-adult size within three months of hatching, although their body feathers remain grey until they begin molting into adult plumage after their first year. Flight feathers develop earlier in the growth period, allowing for fledging by late summer in most individuals.

Vocalization

Despite its name, the mute swan is not truly mute. It produces a range of low-volume sounds, including soft grunts, snorts, and hoarse whistles, particularly during courtship and territorial encounters. When threatened, it hisses forcefully, and pairs communicate with short snoring calls or rhythmic bugle-like trills to maintain pair bonds. One of the most distinctive non-vocal sounds is the loud, throbbing hum of its wings in flight, which can carry over a kilometer and serves as an acoustic signal between swans in motion. Cygnets are more vocal, emitting soft whistles when content and high-pitched peeping sounds when distressed.

Range

The mute swan occupies a broad Palearctic range, with established populations across temperate Europe and extending eastward into western and central Asia. Its core native range includes the British Isles, the Low Countries, Germany, Poland, the Baltic region, and stretches through Ukraine, southern Russia, and Kazakhstan. The easternmost confirmed breeding populations occur in parts of Mongolia and the Russian Far East. In recent decades, the species has expanded its breeding range into northwestern Russia, colonizing shallow eutrophic lakes and island systems. This expansion has slowed in recent decades, likely due to climatic or ecological limitations.

Globally, the post-breeding native population is estimated at approximately 500,000 individuals, with up to 70% located in Russia. Other significant breeding concentrations occur in the United Kingdom, Germany, Denmark, Poland, and the Netherlands. Smaller but stable populations are present in Ireland, Ukraine, and parts of southeastern Europe. Isolated breeding also occurs in eastern China.

In East Asia, three small and poorly studied migratory populations persist. These include birds wintering along the coast of eastern China (originating from Inner Mongolia and southern Russia), birds on the Korean Peninsula, and a sedentary introduced population in Japan. GPS telemetry has confirmed consistent migratory behavior and high site fidelity among individuals in these regions, though the total East Asian population likely numbers fewer than 1,000 birds.

Outside the native range, introduced populations are established in several regions. Mute swans were introduced to North America in the late 19th century and have since become invasive, particularly in the Great Lakes region and along the Atlantic coast. Their ecological impact has prompted management efforts. Smaller introduced populations exist in New Zealand, South Africa, and around Perth in Western Australia.

Migration

Migration in the mute swan is highly variable and primarily influenced by latitude and local environmental conditions. In general, the species exhibits a combination of sedentary, partially migratory, and locally nomadic behaviors across its range.

Populations in northern and eastern Europe are typically partially migratory. Individuals from Sweden, Finland, and the Baltic States move southwest to wintering grounds in Denmark, northern Germany, and southern Sweden. Birds breeding in Ukraine migrate toward the Black Sea coast, the Danube Delta, or further into the Balkans and northern Italy. In contrast, populations in western and central Europe, such as those in the United Kingdom, the Netherlands, and northwestern France, are largely sedentary, although some short-distance seasonal movements do occur. Migration is primarily triggered by the onset of freezing conditions and the availability of open water and food resources.

Post-breeding movements are well defined, with both breeders and non-breeders gathering at traditional moulting sites from July to August. During this period, which lasts six to eight weeks, birds become temporarily flightless and often form large aggregations in suitable wetland habitats.

In East Asia, mute swans follow three loosely defined migratory flyways. Birds wintering in eastern China have been tracked to summering areas along the lower Selenga River in Russia, central Mongolia, and Inner Mongolia. Another population migrates between the Amur border region and the Korean Peninsula. Tracking studies have documented the use of specific stopover sites and high fidelity to breeding and wintering grounds. Migration routes in this region are still being documented, but habitat use appears to be almost entirely restricted to inland water bodies.

In milder regions, winter territoriality is observed, as in parts of the United Kingdom, where pairs may retain exclusive access to high-quality feeding areas. The extent of winter residency is influenced by both temperature and habitat productivity. During severe winters, mass relocations to ice-free areas are common, particularly from inland lakes to coastal zones. Overall, the mute swan demonstrates ecological flexibility in its migratory behavior, with responses varying markedly between populations and geographic regions.

Habitat

The mute swan primarily inhabits lowland freshwater wetlands. Its preferred environments include shallow lakes, slow-flowing rivers, ponds, marshes, and reedbeds. Clean, well-vegetated water bodies are generally favored, particularly those with extensive submerged macrophytes and emergent vegetation. In flowing systems, the species shows a preference for clear, weed-filled streams over polluted or high-flow rivers.

Artificial habitats are frequently used, particularly in human-dominated landscapes. These include reservoirs, canals, gravel pits, park ponds, and ornamental lakes. Mute swans are also commonly observed grazing in adjacent terrestrial areas such as pastures, riverbanks, and cereal fields. Seasonal grazing on grasslands may increase during colder months when aquatic vegetation becomes less accessible.

During the post-breeding moult, swans may relocate to larger wetlands or coastal areas with brackish or saline conditions. These include estuaries, sheltered coastal bays, and brackish lagoons. In such habitats, large moulting flocks can form, often composed of both breeding and non-breeding individuals. In winter, flocks may concentrate in ice-free waters, including inland lakes and coastal inlets, depending on severity of weather.

The species exhibits ecological plasticity, adapting to a wide range of waterbodies, both natural and anthropogenic. However, habitat quality, particularly in terms of food availability and disturbance levels, strongly influences site selection and seasonal movements. Conservation efforts in Europe have shown that management of aquatic vegetation and water quality can affect mute swan habitat use, particularly in wintering and moulting areas.

Behavior

Mute swans are largely diurnal and exhibit a diverse behavioral repertoire structured around a few key mutually exclusive activities: foraging, resting, maintenance (such as preening), locomotion, and social interactions, including aggression. Time-activity budgets reveal that individuals often face trade-offs between these behaviors, with increased investment in one typically coming at the expense of another. For instance, aggression tends to reduce time spent resting, while foraging is often inversely related to both resting and maintenance behaviors.

In wild populations, mute swans allocate a considerable portion of their time to active behaviors, particularly swimming and underwater foraging. Resting and preening are also common but occur in shorter bouts interspersed with more energetically demanding tasks. The species is known for its assertive temperament, especially in territorial contexts. Aggressive interactions, including threat displays and physical confrontations using the wings and beak, are frequently directed at conspecifics and, less often, at heterospecifics, particularly during periods of high population density. Despite this, mute swans are also observed engaging in synchronized behaviors such as group preening, suggesting some degree of social facilitation within flocks.

Captive mute swans display significant shifts in behavior due to space constraints and reduced environmental complexity. Studies show a marked increase in stationary behaviors such as standing, lying, and preening while standing or lying. In contrast, active behaviors like swimming and foraging are significantly reduced or entirely absent when enclosures are small or lack aquatic vegetation. These constraints lead to a more monotonous behavioral profile, occasionally punctuated by abnormal behaviors like pacing, which are rarely observed in wild counterparts. The lack of physical and cognitive stimulation in captivity underscores the need for enrichment strategies tailored to waterfowl, such as floating feeders or larger ponds to support natural movement.

Socially, mute swans form long-term pair bonds and often maintain strong territoriality, especially during the breeding season. Outside of breeding, flocks may be more loosely structured, but dominance hierarchies and individual spacing preferences persist. In mixed-species aggregations, mute swans generally dominate smaller waterfowl, frequently displacing them from preferred roosting or feeding sites through posturing or direct aggression.

Interactions with humans are complex and vary by context. In urban and suburban settings, mute swans often become habituated to people, particularly in areas where they are regularly provisioned with food. They may approach humans with little hesitation and, in some cases, display defensive or even overtly aggressive behavior, especially when defending their territory or offspring. Due to their large size, strength, and boldness, mute swans are sometimes considered among the most dangerous birds. While admired for their grace and symbolic associations, they can become locally contentious due to their intolerance of other waterbirds and occasional conflicts with recreational water users.

Breeding

Mute swans form long-term pair bonds, typically beginning at two years of age, although most individuals do not breed until their third or fourth year. Courtship behavior involves synchronized displays and mutual posturing, and once a territory is established, the male (cob) collects nesting material while the female (pen) constructs the nest. Nests are large, up to 1.5-2 meters (5-6.6 feet) in diameter, built of grasses, reeds, and other aquatic vegetation, and usually situated on shorelines, islets, or floating mats in calm waters.

Clutch size usually ranges from 4 to 12 eggs, with 5 to 6 being typical. The female is solely responsible for incubation, which lasts approximately 35-41 days. During this time, the male plays a key role in territory defense and alert behaviors, allowing the female occasional foraging breaks. Observational studies show that females allocate nearly all their time to incubation and feeding the cygnets, while males devote significantly more time to aggression and guarding, primarily directed at other swans. This distinct division of labor supports the presence of obligate biparental care in the mute swan, despite the species’ temperate breeding range and precocial young – a combination that generally favors uniparental care in other waterfowl.

After hatching, cygnets are precocial and leave the nest within a day or two. Both parents care for the brood, often guiding them to feeding areas and sometimes carrying them on their backs. The family remains together through summer and often into winter, although fledging typically occurs at 4-5 months of age. Cygnets on high-quality territories tend to stay with their parents longer than those on poor-quality sites, possibly due to reduced aggression from conspecifics and better access to food. Smaller cygnets also tend to stay longer than larger siblings, which are more successful in competing for food after independence.

Nest site selection shows marked preferences: in east-central Europe, mute swans breed primarily on oxbows and river bends with nearby open terrain, avoiding heavily forested or densely built-up areas. However, increasing competition with the more aggressive and expanding whooper swan (Cygnus cygnus) may be pushing mute swans out of traditional fishpond habitats, potentially influencing nesting success and altering population dynamics. Continued monitoring of these interspecific interactions is essential to understanding future changes in breeding patterns and habitat use.

Lifespan

Mute swans are long-lived birds, with an average lifespan in the wild typically ranging from 10 to 20 years, though individuals surviving beyond 25 years have been recorded. Exceptional cases include a ringed individual that lived for over 40 years, confirmed in Denmark by the Copenhagen Bird Ringing Centre. This record demonstrates the species’ potential for longevity under favorable conditions and reflects the success of conservation efforts, especially in regions like Denmark and the UK, where populations have recovered strongly since legal protections were introduced in the 20th century.

Mortality factors

Mortality in mute swans arises from both natural and anthropogenic sources. Eggs and cygnets face the greatest risk from predation. Native predators include wild boars, corvids, and red foxes, while northern pike and American mink occasionally prey on cygnets. In non-native environments such as North America, snapping turtles are a notable predator. Adult mute swans, particularly when healthy, are rarely preyed upon due to their large size and defensive aggression, but coyotes, lynx, bears, and in rare cases, golden eagles may pose a threat to injured or weakened individuals. Adult swans are known to successfully repel predators using their powerful wings and have been observed killing red foxes in territorial disputes.

Human activity remains the primary source of mortality. Collisions with power lines, ingestion of lead fishing weights, and attacks by unleashed dogs are all significant causes of injury and death. In urban or suburban environments, conflict with dogs has increased, especially during the breeding season when swans exhibit strong territorial aggression. Legal protections in countries such as the UK reflect both cultural significance and the vulnerability of mute swans to these threats.

Breeding longevity appears to be influenced by individual variation in condition. A long-term study of mute swans in the UK showed that reproductive performance, including laying date and clutch size, improved up to around age 6-7, then declined after age 12, suggesting both age-related senescence and selection for high-performing individuals with longer lifespans. This pattern underscores the importance of individual quality and survival in shaping mute swan population dynamics.

Diet

The mute swan is primarily herbivorous, feeding mainly on submerged aquatic vegetation. Its long neck allows it to reach depths inaccessible to many other waterbirds, enabling it to extract stems, roots, tubers, and leaves from up to 1 meter (3.3 feet) underwater. Preferred food plants include species of Potamogeton, Ceratophyllum, Myriophyllum, and Characeae, though swans may also consume filamentous algae and occasionally graze on grasses and agricultural crops when aquatic vegetation is scarce.

Foraging is typically done while swimming, using the head-dipping and upending technique common to large waterfowl. On land, mute swans may graze short-cropped pasture, especially in winter or when lakes are frozen. In nutrient-rich wetlands such as the fishponds of the Dombes region in eastern France, mute swans share habitat with species like coots (Fulica atra) and diving ducks (Aythya spp.) without evident foraging competition, suggesting that abundant macrophyte availability can mitigate interspecific conflict. Studies from this region found no significant negative impact of swan presence on the distribution of other herbivorous waterbirds, and in fact, higher overall bird abundance where swans were present, likely due to shared habitat preferences. However, in more resource-limited environments or at high swan densities, individuals may defend feeding territories more aggressively, potentially excluding conspecifics or other herbivorous birds from prime foraging areas.

Culture

The mute swan holds a prominent place in European folklore, royal tradition, and classical mythology. Since 1984, it has been the national bird of Denmark, replacing the skylark. Its graceful appearance and dramatic transformation are famously captured in Hans Christian Andersen’s fairy tale “The Ugly Duckling,” in which an awkward, ostracized cygnet matures into a beautiful swan – now one of the most enduring metaphors for inner potential and personal growth.

In classical mythology, swans were sacred to Apollo, the Greek god of music, poetry, and light, and were often depicted pulling his chariot or accompanying muses. The idea of the “swan song,” a final burst of beauty or creativity before death, originated from the belief that swans sing most beautifully just before they die. Although mute swans are largely silent, this legend contributed to the swan’s symbolic association with poetry, art, and the fleeting nature of life.

Swans also appear in the myth of Leda and the Swan, in which Zeus assumes the form of a swan to seduce or assault Leda – an image that has inspired centuries of literature and art. In Celtic and Norse traditions, swans were linked to transformation, purity, and the soul’s journey between worlds. They often appear in tales as magical beings or shape-shifters, moving between human and avian forms.

In the United Kingdom, mute swans have long been bound to royal customs. The monarch traditionally owns all unmarked mute swans in open water, a right still symbolically exercised during the annual Swan Upping on the Thames. This event, dating back to the 12th century, involves the royal swan marker and two London guilds, the Vintners’ and Dyers’ Companies, who also retain partial rights through grants from the 15th century.

Local traditions add further cultural layers. At the Bishop’s Palace in Wells, England, mute swans have been trained for centuries to pull cords attached to bells to signal when they want to be fed—a tradition that continues with the current pair. In Boston’s Public Garden, a pair of swans named Romeo and Juliet charmed visitors for years until it was revealed that both were female.

In Australia, where the native black swan is the state emblem of Western Australia, the Sydney Swans Football Club adopted the mute swan as their mascot to reflect their red-and-white colors. The swan’s wings in the club logo are stylized to mirror the sails of the Sydney Opera House, blending bird symbolism with national architecture.

Threats and conservation

The mute swan is widely distributed across temperate Eurasia and has been successfully introduced to parts of North America, Australasia, and southern Africa. In the UK and much of Western Europe, the species has experienced a strong recovery since the late 20th century, following notable declines in the 1960s and 1970s. In Great Britain alone, the population more than doubled between 1974 and 2012, stabilizing around 2000. The global population is estimated at 598,000-615,000 individuals, with the European population comprising approximately 83,400-116,000 breeding pairs or 167,000-232,000 mature individuals. This growth has been driven by a combination of factors, including the ban on lead fishing weights, changes in agriculture, improved water quality, and milder winters. Although now listed as a species of Least Concern, the mute swan’s local impact on aquatic vegetation, fisheries, and crops has led to ongoing management and conservation discussions.

Threats

Historically, one of the most significant threats to mute swans in the UK was lead poisoning from the ingestion of discarded angling weights. Prior to a 1987 national ban on lead fishing weights, lead toxicosis was identified as the leading cause of mortality in many populations, particularly in areas of heavy recreational fishing. While the ban resulted in a rapid drop in blood lead levels by the early 1990s, further decline stalled by 2000-2001. This plateau may be linked to legacy lead residues in sediment or continued exposure to other sources such as gunshot pellets in agricultural fields. In some regions, ingestion of spent ammunition remains a potential hazard, although the proportion of swan deaths attributable to lead poisoning has declined significantly in recent decades.

Another key concern is conflict with agriculture. In parts of England and Wales, particularly in the east and southeast, mute swans have increasingly grazed on autumn-sown crops, especially oilseed rape (Brassica napus) and wheat (Triticum aestivum), during the winter months. These crops have become a substantial part of the swan’s winter diet, especially when aquatic vegetation is scarce. Reports of crop damage have increased accordingly. Additionally, mute swans can contribute to overgrazing of aquatic macrophytes, leading to competition with other waterbirds and localized degradation of wetland habitats. In fisheries, particularly those managed for angling, their presence is sometimes viewed as detrimental to aquatic plant cover and fish spawning areas.

Conservation efforts

The ban on lead angling weights in 1987 remains the single most impactful conservation intervention to date, resulting in both reduced mortality and a steady population increase. However, subsequent analyses suggest that agricultural change, especially the widespread shift toward autumn sowing of cereals, has played an even more important role in supporting population growth at the regional level. Expanded food availability during winter months likely improved survival rates and breeding productivity.

Efforts to mitigate agricultural conflict have included egg oiling (rendering eggs infertile by applying a thin layer of paraffin) in areas such as Wiltshire and the West Midlands. However, these measures proved labor-intensive and their effectiveness varied with immigration rates and high adult survival. Long-term modeling showed that even complete clutch destruction only stabilized local non-breeding populations, without significantly reducing breeding numbers or alleviating crop damage. Consequently, egg oiling has not become a widely adopted management tool.

Environmental regulations that improved water quality, particularly through reduced phosphorus runoff, may also have enhanced habitat quality for swans by promoting the growth of submerged aquatic plants. In combination with warmer winters, which reduce overwinter mortality and allow for earlier breeding, these changes have helped sustain high swan densities in many areas.

Today, mute swans are a familiar and often charismatic presence in both natural and urban wetlands. Their continued success, however, may bring renewed management challenges, particularly where their foraging habits intersect with intensive agriculture or sensitive aquatic ecosystems. Future conservation and land-use policies will likely influence both their abundance and their ecological footprint at local scales.

Similar species

Several swan species resemble the mute swan (Cygnus olor) either in appearance or range. However, they can be distinguished by differences in posture, bill color, vocal behavior, and geographic distribution.

Whooper swan (Cygnus cygnus)

The whooper swan is similar in size to the mute swan but has a straighter, more upright neck posture and lacks the characteristic S-curve. Its bill is mostly yellow with a black tip, unlike the mute swan’s orange bill with a pronounced black knob. The whooper swan is highly vocal, producing loud trumpeting calls, in contrast to the mostly silent mute swan. It breeds in subarctic Europe and Asia, often wintering in similar areas to the mute swan but favoring wilder, more northern habitats.

Tundra swan (Cygnus columbianus)

Smaller than the mute swan, the tundra swan has a similar white plumage but a shorter neck and a more delicate build. The Bewick’s swan (Cygnus bewickii), its Eurasian subspecies, features a yellow and black bill with more variation between individuals, and lacks the black knob. Like the whooper, tundra swans are highly vocal and gregarious, often forming large flocks. They winter in overlapping regions with the mute swan in parts of Europe but breed much farther north in Arctic tundra.

Trumpeter swan (Cygnus buccinator)

Native to North America, the trumpeter swan is the largest swan species and can be larger than the mute swan. It is entirely white like the mute swan but has an all-black bill and no knob, with a more angular head profile. Its voice is a deep, resonant trumpet call, very different from the quiet grunts or hisses of the mute swan. While their ranges do not typically overlap in the wild, feral mute swans have introduced competition in some North American habitats.

Black swan (Cygnus atratus)

Easily distinguished from the mute swan by its dark plumage and striking red bill with a white tip, the black swan is native to Australia. Despite the color difference, both species share a gracefully curved neck and can coexist in ornamental ponds or introduced populations. The black swan is vocal and social, often seen in large groups, whereas mute swans are more territorial. In regions like New Zealand or parts of Europe, feral populations of both species may occur side by side.

Future outlook

Mute swans have experienced a notable population resurgence across much of their range in recent decades, particularly in the UK and Western Europe. This growth reflects the complex interplay of environmental regulations, agricultural changes, and improved water quality, as well as the species’ adaptability to human-modified landscapes. However, local overabundance in some areas has brought new challenges, including habitat degradation and conflict with agriculture, leading to targeted management interventions.

Looking ahead, mute swan populations are expected to remain stable or increase in many regions, though future trends will likely be shaped by broader environmental pressures. Climate change, land-use policy, and potential shifts in agricultural practices may all influence habitat quality and food availability. Continued monitoring and adaptive management will be key to balancing conservation success with ecosystem health and minimizing conflicts. As a species deeply integrated into human-dominated environments, the mute swan’s future will be closely tied to how those environments evolve.

Further reading

• 24 of the world’s largest flying birds by wingspan, weight, and height
• 12 of the world’s most dangerous birds and what makes them aggressive