- If we repeatedly find only pairs, it means they have not bred successfully, or their chicks have died.
- On the other hand, an increase in the size of family groups shows breeding success.
Knowing about family ties also increases the likelihood of successfully releasing Operation Nest Egg subadults. With rowi, for example, family groups are exceptionally territorial, so we now know to release subadults well away from occupied territories.
The role of family groups intrigues kiwi researchers. They have been recorded for some taxa but not others, and there are even variations within tokoeka—while there is nothing to suggest Haast tokoeka form family groups, they are found in the three other tokoeka taxa.
Researchers also think great spotted kiwi may form family groups. Family ties appear to be much weaker than in Stewart Island tokoeka or rowi, but great spotted kiwi chicks stay within the territory they were born in, and are occasionally found with their parents. One possibility is that family groups may last longer in high-density populations because young birds get beaten up by the neighbours if they leave their parents’ territory.
Future research priorities
Priorities for research into species and population dynamics include:
- Gathering more information about great spotted kiwi and Fiordland tokoeka so that accurate population modelling can be done.
- Finding out about the ecology and behaviour of all kiwi species, but particularly South Island species.
- Establishing why Haast tokoeka and rowi are low breeders and have small populations, and coming up with ways to overcome these things.
- Finding out more about what causes low fecundity (fertility). It can be linked to several things—few adults may attempt to breed, those who do may have low fertility, and/or few fertile eggs may hatch. It is also linked to soils of low fertility, inbreeding depression, and birds becoming unproductive because of old age.