Swanlets › Cygnets: nesting season and growth stages
Cygnets: nesting season and growth stages
A cygnet takes about five months to be able to fly and a full year to look like its parents. Here is the swan year, stage by stage, with notes on what is normal.
Nesting season
Mute swans usually pair for life and return to the same territory each year. The male, called a cob, and the female, the pen, start building in March. The nest is a big mound of reeds, sticks and water plants, often beside water, and it can be reused and added to for years. The pen lays several large pale eggs, commonly four to seven, in April or May, with a gap of a day or two between them. She does most of the sitting, and the cob stands guard.
Incubation lasts roughly five to six weeks. Because the eggs are laid over several days but incubation starts when the clutch is mostly complete, the cygnets tend to hatch within a day or so of each other. Most UK hatchings fall in late May and June, but it varies with weather and region.
Cygnet growth stages
| Age | What you will see |
|---|---|
| Hatch to 2 weeks | Pale grey down, pink bill and legs. They often ride on a parent's back and stay close. |
| 1 to 2 months | Rapid growth. Down turns darker grey-brown and the first feathers appear. |
| 3 to 4 months | Mostly feathered, brown-grey and gawky. Wings are developing but not ready to fly. |
| About 4 to 5 months | Fledging. Cygnets begin to fly, usually in the autumn. |
| 6 to 12 months | White feathers come in patchily through winter. The bill darkens towards orange. |
| Around a year | Mostly white, though some brown may remain. They are driven off the territory before the next breeding season. |
These are typical timings, not exact. A cool wet spring or a lack of food can slow things down.
Why cygnets are grey
The grey-brown plumage helps camouflage young birds in reeds while they are small and vulnerable. It is the origin of the old "ugly duckling" tale: the story's hero was a young swan raised among ducks. Swans do not reach breeding age straight away. They usually begin breeding at about three or four years old.
How many cygnets survive?
Not all of them. Cygnets can be lost to foxes, mink, large pike, bad weather, flooding that washes the nest away, and disturbance. Pairs that lose a clutch very early may lay again. Seeing a pair with fewer cygnets in July than in June is normal and not a sign of neglect.
Living near a nest
- Keep dogs on a lead and well away, since a cob will defend his territory and may chase or hit with his wings.
- Do not feed cygnets by hand or crowd them. Read our advice on feeding swans properly.
- Do not move eggs or try to "help" a nest. It is an offence to disturb a nest in use; see the swan law page.
- If you find a cygnet alone, watch first from a distance. Parents are often nearby. If it is clearly hurt, see what to do for an injured swan.
Cygnets in winter
By autumn, young swans may form flocks with other non-breeders. This is a good time to watch them preen and practise flying. Check our identification page before logging any grey swan, because young whooper swans are also greyish.
Frequently asked questions
When do cygnets hatch in the UK?
Mostly in late May and June, depending on the weather and the region.
How long do cygnets stay with their parents?
Usually until the following spring, when the parents drive them off before breeding again.
Why are cygnets grey?
Their grey-brown feathers give camouflage while young; they turn white over their first year.