Why Mast Season is a Perfect Time to Get Trapping

predator-cycle-diagram, DOC.govt.nz
predator-cycle-diagram, DOC.govt.nz

predator-cycle-diagram, DOC.govt.nz

You might have heard that this year is a mast season in our beech forests, which is why DOC are taking action. But you may not know it is also a perfect time to get trapping in your own back yard.

What the heck is a mast season? It is when the weather conditions over the summer are perfect for our native forests to flower heavily and produce a bumper crop of seed. This is most noted in the beech forests of the South Island but seems to have a similar impact on many of our native trees.

During Autumn (now) the plentiful seed falls on the forest floor. In the past that would have been a bumper crop for our native birds, but nowadays it mostly becomes rat food. Rats can breed 20-30 times faster than our native birds, producing five litters of up to 14 rats every year. So this surplus of food will mean that by next spring our forests face a plague of rats and stoats (which feed on the rats).

When the seed runs out, the rats and stoats turn on our native birds, eating their eggs and chicks in Spring. This spells disaster for our native birds. As an example, the last mast season in 2000 led to the yellowhead (mohua) all but disappearing from the Marlborough Sounds. Numbers of the bird on Mt Stokes, near Kenepuru Head in the Marlborough Sounds, dropped from 130 to only five. DOC estimate that without action our remaining mohua population could be reduced by 75%. That’s right – they are the bird on our $100 bill.

So this year our native birds will truly be under siege. This is why DOC has declared the ‘Battle for our Birds’ to nip this population explosion in the bud before our native birds are affected. The same thing seems to be happening – to a lesser extent – on our own urban fringes. That is why it is a perfect time to get trapping in your own backyard.

Mast seasons are most noticeable in beech forests, but they do seem to happen in the podocarp forests of the North Island also. DOC rangers report bumper crops of seed in totara and rata forests, and around the cities trees like the ti kouka (cabbage tree) seem to be producing well also. This is likely to have a similar impact on rat populations in the North Island as it does in the beech forests of the South. There has never been a better time to get a rat-trap into your back yard to help protect our native birds.

So visit our trapping page, grab yourself a cheap trap with the code (PESTBUSTER) and get trapping.