Kiwi couples have been known to last more than 20 years – every third day or so they come together to share a burrow, and at night they perform duets, calling to each other.

However, divorces are also known, especially in high-kiwi density areas in Northland. 

Breeding Season

The main kiwi breeding season runs from June through to March, when the kiwi's food supply is most plentiful.  The exception is Brown Kiwi which can lay eggs in any month.

In captivity, male kiwi can reach sexual maturity at 18-months, and females can lay their first eggs at about three years of age. 

In the wild, kiwi usually do not breed until much older.  Wild females lay their first eggs at 3 - 5 years of age.

Unlike bird species that can entice their mate with colourful plumage or a beautiful song, the male kiwi has drab brown feathers to work with.  Instead, he has developed the strategy of persistence to win his larger mate’s attention.  The male follows her about, grunting. If uninterested, she may run away, or use her greater weight and size to see him off.  However, if she is interested, mating takes place, three or more times a night during the peak of activity.

Mating Behaviour

During mating, the male taps or strokes the female on her back, near the base of her neck. She crouches low with her head stretched forward and resting on the ground. Because the female is the larger bird, the male needs her full co-operation to successfully mate.  He climbs onto her back and balances precariously during mating – with no wings or tail this can be rather difficult. Often he will grasp the hen's back feathers in his beak to help his balance.  

The kiwi female calls the shots during mating.  If she loses interest she may wander away, leaving the male in an undignified heap on the ground.

A kiwi pair mate about three weeks before the egg is laid. 

Two Functional Ovaries

Another unusual fact about kiwi is that females have two functional ovaries.  In most other birds only the left ovary develops.  While only Brown Kiwi regularly lay more than one egg in a clutch, when this occurs, ovulation happens alternately in each ovary.

Next: The female produces an egg