Do Swans Mate For Life?

We’ve all seen those romantic photos, with a pair of loved-up swans forming a perfect, symmetrical heart shape with their long necks. Pairs are said to form strong bonds, but is that true for all species? Do all swans mate for life?

We’ll be looking at what happens when a swan’s mate dies, and learning more about the family dynamics of a group of swans and cygnets. If this is something you’re keen to learn more about, then please read on!

Mute swans have a reputation for forming lifelong relationships with a mate, and even dying of a broken heart when their partner dies. But this is not always the case for all swan species, or even for all mute swans. Some widowed swans seek new mates, while other species are not always monogamous.

Mute Swans generally form lifelong bonds with their partners, meaning they mate for life

While many swans will remain with the same mate for the duration of their life, it is not unheard of for a swan that loses its mate to seek a new partner rather than spending the rest of its days pining.

It’s also not unheard of for copulation to occur with a different mate, with a study of Australian black swans showing that around 1 in 7 cygnets were raised by a male that was not the biological father.

Read on for more insights into swan relationships, from courtship rituals to how swans cope with the aftermath of bereavement of a mate, and even the unusual event of 'swan divorce'.

A breeding pair of Australian Black Swans

Do all Swan species mate for life?

Swans in general are known as monogamous birds, with different species all exhibiting loyal and faithful bonds with their chosen mate. However, despite the formation of lifelong bonds, divorce and promiscuity are observed in a small percentage of pairings each year.

• Mute swans form strongly bonded pairs with the intention of remaining together for life, which is usually the case – in 97 percent of pairs.
• Trumpeter swans are another species that typically mate for life, with bonds usually formed between the age of 5 and 7 years.
• After forming a pair, Tundra swans spend a year together before their first breeding attempt and will generally remain together until the eventual death of one of the pair, up to 15 years later.
• Whooper swan pairs remain bonded for a lifetime after their initial pairing, except in the rarest of circumstances.
• Research suggests that Bewick’s swans are the least likely to divorce a mate, which is suggested to be in part down to the fact that pairs embark on long-distance migrations together.
• Australian black swans are classed also as monogamous birds, and as is the case with other swan species, the general consensus is that they, too mate for life. Surprisingly, observations show that up to 38 percent of cygnets are born from copulation with a different mate.

Trumpeter swans usually mate for life

Why do Swans divorce?

Swan species generally display a level of faithfulness and loyalty to a mate that is unmatched in other bird species. However, swan 'divorce' is a rare but real phenomenon, and has been observed on occasions where both former partners have returned to a spring breeding site with a new partner in tow, showing no acknowledgment for their former mate.

Data puts the swan divorce rate at around 3 percent of pairs annually, citing reasons of unsuccessful breeding attempts as a possible catalyst. For swan pairs that have failed to raise young, the rate is as high as 9 percent.

For Bewick’s swans, separation of a mated pair is particularly rare, with only one example recorded in over 4,000 pairs observed at a UK wildfowl sanctuary over the course of 40 years.

Bewick's Swan separation is highly rare, with only 1 recorded split in over 4,000 breeding pairs in the UK

How do Swans attract a mate?

Swan mating rituals follow an elaborate pattern of dramatic displays, with graceful movements mirrored by both male and female birds. A male swan (known as a cob) will begin giving out vocal signs to attract a mate, such as hissing in some species and a low-pitched trumpeting call in others. Calls are accompanied with tail flicking and wing flapping. If she is interested, the female (known as a pen) will respond.

Head bobbing and dipping become synchronized if both cob and pen decide they want to proceed with forming a pair.

This is followed by both birds extending their necks and reflecting each other’s movements, becoming closely entwined chest to chest, which is where the “swan-neck heart” imagery comes in.

A pair of Mute Swans during a courtship display

How many times a year do Swans mate?

Swans breed once a year, and stay with their young for an extended period afterwards. In the southern hemisphere, breeding takes place between August and October. In Europe and North America, mating takes place ahead of the breeding season in March to May.

Swan pairs may also continue to mate sporadically even when eggs have been laid, and this is thought to be a way of strengthening their pair bond.

What happens when a Swan mate dies?

After a swan’s mate dies, there may be a period of deep grief as the surviving mate adjusts to its new single status. Some widowed swans may never recover from the intense grief and loss of companionship and take little care in feeding themselves or preening.

In the most tragic of circumstances, this lack of self-care can lead to the premature death of the surviving mate.

In other cases, the bereaved swan may move on to new waters almost immediately in search of a new mate and new opportunities for breeding and raising young. Females are observed to be more successful in finding a new mate than males.

Swans are highly sociable, and thrive in pairs

Do Swans mourn the loss of a mate?

Some swans may experience and display intense grief and loneliness on the death of a mate. They can become withdrawn and lose interest in feeding or taking care of their young.

Losing cygnets can also have a similar effect, with the brokenhearted, bereaved parent bird unable to function after the trauma of the loss.

Swans are highly social birds and thrive in pairs. While some may slip into a deep decline after the death of a mate, others will immediately seek a new partner, and on average, if re-pairing occurs, a widowed female may successfully secure a new mate within 3 weeks.

Pair of Trumpeter Swans in flight over a field

Do Swans mate with their siblings?

The short answer to this question is that, yes, occasionally swans may end up mating with their siblings, but it is not common or usual practice.

Cygnets stay with their parents until the spring after they hatch. After this time, they either leave of their own accord or are driven off by their parents and join a new flock away from their family. This is usually the first group of swans they encounter.

Once ready to mate – at around 3 years of age – they pair up with a mate, usually from the flock they are part of, and leave to establish their own breeding territory together.

It’s unlikely that the bird they pair with will be a sibling, but if both unpaired birds end up as part of the same flock after leaving their family, then it is not impossible.

A pair of Whooper Swans in winter

Do Swans migrate with their partner?

Not all species of swan migrate, but those that do will generally remain with their partner throughout the winter months and return together to their familiar breeding grounds in the spring.

Do Swans stay together as a family?

Swans are known to be fiercely protective over their cygnets while they are growing and reaching independence, but how long does this instinct last, and is the bond between parent swans and their young as strong as the bond between mates?

After spending the winter after they have hatched together, juvenile swans are on borrowed time with their parents. As spring approaches, many newly mature swans will leave their home territories to join new flocks.

Those that initially stay with their parents will soon be driven away by their mother and father, whose thoughts have already turned to the new season’s upcoming brood.