A mast year in New Zealand is now a serious threat to the native birds of New Zealand. Read what it is and why it’s a danger to NZ’s birds.
Prior to the arrival of people mast years were a great time for New Zealand’s wildlife. It meant there would be an abundance of food for them and they would thrive. Unfortunately, people have introduced many species to the islands of New Zealand and a mast year now has a very different connotation. For conservationists a mast year is something to be worried about because the native birds will be under attack by the introduced predators.
What Is A Mast Year?
It is a year in which the trees of New Zealand produce huge amounts of seeds.
Many of the native trees of New Zealand go several years without producing much seed. Then every 2 – 6 years they go crazy and make tons of seeds. This is known as a mast year.
The south island has huge areas that are dominated by beech trees. These beech forests have some years in which they generate huge amounts of seeds.
Why Is A Mast Year A Problem For New Zealand’s Birds?
In the past a mast year meant that there was heaps of food available for New Zealand’s native wildlife. Unfortunately, with the introduction of many species, especially the big three predators (rats, stoats, and possums), this has changed.
A year of a huge seed fall is good news for these introduced species and bad news for native wildlife. Scientists have figured out that a mast year leads to a number of effects with the final one being the native bird populations plummeting or being wiped out. Many native bird species already have low populations and a mast year could cause them to become extinct.
Mast Year Cycle
First – the trees produce huge amounts of seeds, which drop to the forest floor.
Second – this huge amount of food is consumed voraciously by rats. This large amount of food resource leads to an explosion in the rat population.
Third – the increase in the rat population leads to an explosion in the stoat population. This is because the stoats eat the rats and more rats means more food for stoats.
Fourth – over time the amount of seeds as food disappears. Then the rats begin to die off, causing less food to be available for the stoats.
Fifth – the stoats and rats turn to other food sources, namely the native birds and their eggs. It’s like creating a huge population of predators and then turning them loose on the native birds.
What Can Be Done To Protect Native Birds During A Mast Year?
I don’t want to spend too much time writing about this here as this is a lengthy discussion. Essentially, to save the native bird populations, the rats and stoats need to be killed before they can turn their attention to eating the native birds. Various methods are used, but the main one now is using 1080.