What Do Swans Eat? An Overview of Swan Diets and Foraging Behavior

Giant but graceful, swans are larger and heavier than many birds of prey, including eagles and vultures. But just what type of diet is needed to power these magnificent waterbirds? Read on to discover what foods swans eat and how their diet changes throughout the year.

The diet of swans is mainly plant-based, with aquatic vegetation, including pondweed, algae and waterside grasses. To a lesser extent, invertebrates and amphibians are also eaten, and in winter, it’s common for swans to head onto dry land more regularly in search of seeds and grasses.

Swans are most commonly found in the northern hemisphere, although some species are present in Australia, New Zealand and South America. Their typical habitats are freshwater wetlands, lakes and rivers and saltwater marshes, and naturally, their diet reflects what is available where they live.

Read on to learn about what swans in different parts of the world eat, how they catch their food and how humans can safely feed these majestic waterfowl.

A pair of Mute Swans. The diet of swans is mainly plant-based, with aquatic vegetation, including pondweed, algae and waterside grasses

Overview of a Swan’s Diet

Swans are mainly herbivorous, with aquatic plants and grasses forming their main diet. Some insects and invertebrates may also occasionally be eaten - keep reading to find out just what swans do and don’t eat, and whether young cygnets and adult swans eat the same.

Plant matter makes up the bulk of a swan’s food intake, including aquatic vegetation, algae, grasses, grains and leafy greens. Pondweed, duckweed and waterweed all feature heavily in a swan’s diet. Swans forage both on water and on land, where they graze on grass for shoots and seeds.

A smaller share of a swan’s diet consists of insects, molluscs and crustaceans, particularly crayfish and freshwater shrimps. Tadpoles and small frogs, toads and news may also be eaten, often unintentionally as they get caught up in the pondweed or algae swans feed on.

Cygnets initially need to eat softer foods than adult swans, and their early diet consists of aquatic plants and small aquatic insects.

Feeding Habits of Swans

Upended swans, dabbling beneath the surface of a lake or pool are a common and almost comical sight. What we can’t see is their outstretched necks, tugging at the roots of aquatic plants that they dislodge from the lake’s bottom to eat. Read on to learn more about the feeding habits of swans.

The swan’s long neck is its most effective tool for foraging for food. Swimming on the water’s surface they are able to reach floating plant matter, including algae and pondweed with little effort. By upending their bodies, their long necks are able to reach plants that are growing deep underwater, or kicking with their huge feet to disturb any vegetation beneath the water’s surface and stirring it to the top so it’s easier to find.

On land, swans will happily graze for shoots and seeds on fields of short-cropped grass.

A pair of upended Swans. By upending their bodies, their long necks are able to reach plants that are growing deep underwater

Aquatic Plants and Algae

Swans spend a significant part of each day foraging for plant matter on the surface of lakes or just below. To learn more about the types of aquatic plants and algae that are key to the diets, read on.

Aquatic vegetation is the chief element of a swan’s diet, with underwater plants, such as pondweed, duckweed, waterweed, and algae among the most popular food sources.

Weeds, water grasses, and algae are important sources of fiber, carbohydrates, vitamins A, C, and K, calcium, magnesium, potassium, and vital antioxidants. Plant matter provides essential phytonutrients to a swan’s diet, which boosts their overall health.

Swans that live on freshwater typically enjoy pondweed, stonewort, and wigeon grass, while those living on saltwater marshes eat sea arrow grass, salt marsh grass and eelgrass.

Insects, Fish, and Amphibians

Although primarily vegetarian, all swan species do occasionally eat insects, fish, crustaceans, molluscs and small amphibians, either intentionally or as an added bonus when swallowing underwater weeds. Read on to learn more about the animals and insects that may be eaten by swans.

While at least 80 percent of a swan’s diet is plant-based, the remaining 20 percent consists of key protein sources, including fish, insects, small freshwater crustaceans and molluscs.

Tadpoles, water snails, slugs, worms and larvae are occasionally eaten by swans while foraging on lakes, and on rare occasions, water beetles and pond skaters may also be caught.

Grains and Seeds

Grains and seeds are another important element in a swan’s diet, particularly later in the year when energy-rich foods help to boost their energy reserves ahead of migration or to help sustain themselves through the winter. Keep reading to learn more about which grains and seeds swans prefer.

Grains and seeds that swans often eat include cracked corn, wheat and wild rice. Berries may also occasionally be eaten, particularly in winter months.

Mute Swans feeding on cracked corn by the waters edge. Grains and seeds are another important element in a swan’s diet

Swans’ Diet in Urban Areas

Swans are a common sight on lakes and ponds in suburban parks, alongside ducks and geese. They’re instantly recognizable with their snow-white plumage, although people may be hesitant to approach them too closely due to their reputation for being rather aggressive and intolerant. Read on to learn about how to safely feed swans in the wild.

Feeding swans on a public pond offers an ideal opportunity to see these majestic, graceful birds up close… well, maybe not too close! We’ve all heard stories about friends of friends who had their arm broken or their pet dog attacked by an angry swan, so although these are usually cautionary tales or urban legends, it’s wise not to get too near, and to keep any interactions from a reasonable distance.

Feeding bread to swans is not encouraged due to a lack of nutrients, although it is not particularly harmful in small quantities. Peas, chopped lettuce and spinach are popular choices.

Foods not to feed to swans include raw meat, avocados, caffeine, chocolate, and anything with added salt, excess oil, onions, garlic, apples and nuts. It’s sensible to avoid any foods that are not found in their natural environments.

Mute Swans feeding in a lake. Swans are a common sight on lakes and ponds in suburban parks, alongside ducks and geese

The Impact of Diet on Health and Lifespan

A healthy diet with a balance of nutrients, including vitamins and proteins is vital to support the growth, development and overall survival of swans. Read on to learn how a swan’s diet influences its chances of survival and reproductive success.

The plants that form the majority of a swan’s diet - waterweed, pondweed, and various grasses - are rich in essential nutrients, vitamins, and minerals that help their immune system to function properly, keeping them healthy and able to resist any disease. These nutrients also support healthy development and cognitive activity, which contributes to a long and healthy lifespan of between 20 and 30 years.

A swan’s diet also influences its ability to reproduce successfully. Swans in prime health due to a balanced diet will be most likely to attract a mate, while diets rich in calcium, gained from pondweed, duckweed and aquatic grasses, are especially important to females in the breeding season, in order for them to produce strong enough shells for their large eggs.

A Swan foraging at the bottom of a lake. A healthy diet with a balance of nutrients, including vitamins and proteins is vital to support the growth, development and overall survival of swans

Cygnet Nutrition

Cygnets grow rapidly in the initial months of life, from around 8 oz to 10 oz on hatching to a mega 20 pounds by the time they are 5 months old. Read on to find out more about what foods help support the early development of cygnets.

Swan parents accompany their young on foraging missions from their second day after hatching. For up to 10 days, young cygnets require no additional nourishment, as they absorb the rich nutrients from the remains of the yolk of the egg they hatched from.

Although no direct feeding from parent to young occurs, cygnets are led to their foraging grounds with an abundance of aquatic plants. There, they learn by observing adult birds feeding, skimming the water with their long necks, or upending beneath the water’s surface and feeding on underwater vegetation. Adults also stir up underwater plants so they float to the top, making it easier for cygnets to find food.

Similarly, cygnets master the art of grazing by watching their parents in action on dry land.

By 3 to 4 months, cygnets become more skilled at foraging independently, although may still need protection from their parents, gradually becoming more self-sufficient with time and experience.

A Mute Swan and her cygnets feeding in a stream. Swan parents accompany their young on foraging missions from their second day after hatching

Conservation and Environmental Impact on Swan Diet

Swan habitats are under threat from development, pollution and climate change. These factors can influence the availability of food, and therefore the ability of swans to survive in their traditional breeding and wintering ponds. Read on to learn about how conservation efforts can help swan populations.

Loss of wetlands to development and the pollution of ponds, lakes, and streams are two key concerns that are leading to a decline in suitable habitats for swans. When lakes or ponds dry up, swans can lose both foraging opportunities and nesting sites. Climate change increases the temperature of water; even the most subtle rises can cause irreversible changes to plants that are able to grow.

Conservation efforts to restore wetlands are crucial for swans to be able to forage for the foods they need to survive on and in the water as well as on land. Pesticide-free farming is a step towards keeping lakes, rivers and ponds free from pollution that may kill off the aquatic vegetation swans rely on for much of their daily diet.

A Black Swan feeding her cygnets. Swan habitats are under threat from development, pollution and climate change

Seasonal Dietary Changes

The food swans eat is influenced by what is seasonably available and present in their environments throughout the year. Read on to learn about a swan’s typical diet at different times of the year.

In spring and summer, vegetation is the most important and available dietary element, and swans feed on shoots, grasses, fresh pondweeds, leafy green plants and aquatic vegetation. Grains also provide some key nutrients during the breeding period.

As autumn approaches, swans’ diets switch to energy-rich foods to boost their fat reserves ahead of lengthy migration journeys. Farmers’ fields can be a good source of grains and seeds that are rich in protein.

As well as seasonal changes, the diet of different swan species varies according to their habitats. Mute swans are commonly found in temperate regions and primarily feed on aquatic plants, grasses and grains. They graze in shallow water or on land near lakes and ponds.

Tundra swans live in Arctic and subarctic regions and have a diet that consists mainly of aquatic plants, such as pondweeds and sedges. They may also eat some insects and molluscs.

Bewick's swans, which breed in the Arctic and winter in Europe and Asia, have a diet similar to Tundra swans, focusing on aquatic plants and grasses. Overall, the specific diet of each swan species reflects the availability of food sources in their respective habitats.

Mute swans are commonly found in temperate regions and primarily feed on aquatic plants, grasses and grains

A Bewick's Swan foraging. They breed in the Arctic and winter in Europe and Asia and have a diet similar to Tundra swans, focusing on aquatic plants and grasses

Feeding Behaviors and Etiquette

Feeding swans can be a memorable experience, but it’s important to keep the experience as safe and ecologically sound as possible. Read on for some tips about recommended etiquette when feeding wild swans.

There is no harm in feeding swans in the wild, as long as suitable food is offered and you are mindful to cause as little disturbance to their natural habitat as possible. The same applies to watching swans foraging for food on the water. Remain a safe distance away, and keep as quiet and calm as possible; this allows them to continue to feed naturally rather than feeling threatened by your presence.

Any food fed to swans (it’s recommended to offer grains or chopped greens), should be thrown onto the water’s surface so that swans can swallow water when eating. Feeding swans on land is not recommended for environmental reasons as it can leave excess scraps or unwanted food waste on the shore.

Feeding on land also encourages swans to associate humans with food, and may encourage them to leave the water when they spot people, which can put them at risk from vehicles, pets, etc.

Summary

Although swans may eat some small amphibians, insects and crustaceans, their main diet consists of aquatic vegetation, and pondweed, duckweed, and water grasses are by far the most important elements.

They feed by filtering particles of plant matter from the water’s surface, and also from reaching longer plants growing from the bed of the river or lake they inhabit. Grazing on land for grass, grains and seeds is also common, particularly in winter months when underwater plants might not be as readily available.

Respecting the natural diet of swans, and feeding them only when they are on the water are simple ways of keeping swans healthy and safe. Many swans are migratory, departing for ice-free waters as soon as temperatures drop, and the availability of suitable foraging wetlands as stopovers on their journeys is vital for their long-term survival.

A Black-necked Swan. Swans feed by filtering particles of plant matter from the water’s surface, and also from reaching longer plants growing from the bed of the river or lake they inhabit

FAQs

What should you do if you find a swan that appears to be hungry?

It’s wise to keep a safe distance from any swan, let alone a hungry one. You can offer natural foods, such as chopped greens, corn, peas or grains, and ensure that it has access to water. If it looks unwell or in poor condition, the best thing to do is seek advice from a local wildlife refuge.

Can swans eat bread?

Swans can eat bread, but it’s not particularly healthy for them to do so. If you’re going to feed bread to a swan, it needs to be fresh with no signs of mold, and wholewheat options are preferable to white bread.

How do swans find food in winter?

If a swan’s usual waters become frozen in winter, it’s likely that they will migrate in search of frost-free open waters. They are also known to rely more on humans for food in winter months. Grazing on nearby fields for leftover crops and grains is another way they survive when water temperatures drop.

Do swans share food with their mates or offspring?

Although swans do not directly feed their young, they have been seen to indirectly help their young and their mate to access food supplies, by dislodging plants from beneath the water’s surface where they are easier to reach and feed on.