A breeding cob with large black berry.

The Life Cycle of the Mute Swan 

Swans usually pair for life and have elaborate courtship rituals including the famous heart shape they make with their necks.  They normally start breeding in their fourth year.

The male, or cob, is larger than the female or pen and when together the longer neck, larger webbed feet and larger black berry of the male make identification much easier.  Immature birds are difficult to sex.  Male swans can weigh between 9 to 18 kgs, the female 9 to 12 kgs.  They are the largest flying bird and can fly up to 60 mph, although 20 - 30 mph is the norm.  Unfortunately many young swans die each year but some live to about 25 years in favourable conditions.

The cob will establish a territory large enough to supply his future family with sufficient food and will valiantly defend it against all comers, whether they be other swans, foxes or intrusive humans.  Swans are protected birds and it is illegal to harm them or steal their eggs.

The male and female choose the nest site together and use any material within about 40 feet to make the nest.  The pen lays between 1 to 12 eggs, the average being 6.  The eggs are laid every other day and only when the last egg has been laid does incubation start.  The incubation period lasts about 35 days and the pen only comes off the nest for very short periods to drink and stretch her legs.  The cob takes over after a recognition head lifting ceremony.  The cob will defend the nest against foxes, dogs and other predators.

The swan family is very close and if a cygnet is lost, the parents will often look for it up to a week.  Natural predators are pike, foxes, mink and cold wet weather.  Unfortunately man poses further hazards.

Nature has been clever with the swan's moulting period when they cannot fly.  The moult takes about 6 weeks and for non-breeding birds takes place about July time.  A pair with cygnets moult at different times, first the pen and then the cob in August to September so that one of them can always defend the young.

The cygnets learn to fly when their flight feathers have grown from about four and a half months onwards, usually around September time.  This is a dangerous time for cygnets as the autumn months often bring strong winds and the inexperienced fliers can fly into overhead power cables or injure themselves in crash landings.

In the winter food is scarce and the cob may drive his young off to fend for themselves.  Some pairs, however, keep their young with them until they breed again the next season.  The cygnets find their way to non-breeding flocks and this is where they will eventually find a mate.

A cob seeing off an intruder in his territory.

A pen on a nest of reeds built high to avoid flooding.

These eggs were abandoned. It is illegal to take swan eggs or disturb the nest site in any way.

A swan family with cygnets only a few days old.