All living things have a different life cycle. They change and develop at different times and in different ways. Some organisms, like sandflies, are born, mature and die all within a few months. Others, like kauri trees, continue to grow for thousands of years.

Some animals change into completely different forms during their life cycle. This process is called metamorphosis. The huhu beetle or tunga rere begins life as an egg. The egg hatches into a grub, or larva, which looks more like a worm than a beetle! The grub eats plenty to get ready for the changes to come. Eventually, the grub will change into a pupa, with a protective covering around it. Inside this pupa, the larva breaks down into a soupy mixture that is then reassembled into the adult beetle. The adult breaks out of the pupa looking like a totally different creature!

To keep the life cycle going, once a plant or animal has grown into an adult, it begins to reproduce and make new babies of its own. Eventually all plants and animals will die, but as long as new babies are always being made, the cycle of life will continue on and on.

The life cycle of a tui

Adult and tui and nest (click for enlargement)

Every summer, between November and January, female tui lay between two to four eggs in a nest of twigs that rests in a tree fork or on an outer branch of a shrub. The white eggs with light brown splotches take about 14 days to hatch.

Tui nest with chicks (click for enlargement)

When the chicks hatch, their mother and father will feed them small insects and nectar and then later on fruit as well as spiders and larger insects, including moths. The young fledge at about 21 days.

Tui nest (click for enlargement)

This means they leave the nest and begin finding food for themselves. After they have fledged, the young birds usually stay close to their parents for at least a couple of months. Once they are old enough, many tui even make their own nests near the same place that they were born.

Tui often travel in groups with other family members. They may fly long distances in search of food together and return to the same breeding area each year. These trips may help the young tui learn where to find food, which will help them survive over winter when food is hard to find.

How does the tui help plants?

Because tui drink nectar from flowers and eat fruits, they help many plants reproduce.

Flowering plants reproduce by producing seeds that will one day grow into new plants. Seeds are made through a process called pollination. Pollination usually happens when pollen grains are moved from one flower to another.

Birds like the tui help in pollination because when they visit flowers (watch this video - 500Kb)in search of nectar, they may get pollen stuck on their cheek, throat and head feathers. When they visit the next flower, the pollen rubs off and fertilises the flower so that it can produce seeds. The plant covers the seeds that it has made in a juicy fruit, which the tui also loves to eat. When the tui eats the fruit, the seeds go through the bird's gut and end up in the bird's poos. The tui may fly a long way before it poos, so the seeds can end up being pooped out in a new spot far away. In this way plants can be moved away from their parents and start new populations.

Without tui and other birds, some native plants would have a hard time making new seeds and getting them to new places where they can grow. What do you think would happen to our forests if plants continued to die as they got old, but no new plants were made?