Wild, remote, rugged – a last stronghold in the south-west of New Zealand, the Murchison Mountains are home to the last remaining wild population of takahē.
Lost, presumed extinct, the remote alpine tussock basins of the Murchison Mountains on the western side of Lake Te Anau hid the takahē for 50 years until their re-discovery in 1948. Following the re-discovery, the Murchison Mountains were declared a ‘takahē special area’, off limits to all except a few scientists and deer cullers.
For 65 years takahē conservation focused on boosting the wild population in the Murchison Mountain as the means of saving takahē from extinction. ‘Excess’ fertile eggs were gathered from wild takahē nests and taken to Burwood Takahē Centre where they were artificially incubated and chicks hand-reared. Captive reared takahē were either returned to the Murchison Mountains or were used to establish island ‘insurance’ populations.
Eggs are no longer gathered from the Murchison Mountains, nor are birds annually released back into the Murchison Mountains. Today the main focus is on breeding birds at Secure Sites to build and support the population of takahē at Secure Sites.
Testing and refining the effectiveness of stoat and deer control in support of wild takahē adult survival is now the focus of takahē conservation work in the Murchison Mountains
Life is tough in the takahē’s alpine home, but by 2007, things were looking up. The population in the Murchison Mountains had almost reached 200 birds when disaster struck. Following a beech and tussock mast (a mass seeding of beech trees and tussocks which happens every few years), the mountains were besieged by a plague of stoats. Within the span of a few months the wild population of takahē was halved.
Fortunately by this time takahē populations had been established on secure pest-free islands – insurance against just this sort of disaster.
Perfecting pest control
Following the 2007 stoat plague trapping was extended from a trial area of 15,000 hectares to cover the entire 50,000 hectare Murchison Mountains Specially Protected Takahē Area.
Trapping continues to be refined to improve the protection to takahē and other species. Trapping effort has been intensified by reducing the spaces between traps along trap lines, increasing the number of trap lines and increasing the frequency of trap checks.
Currently 2500 traps are checked, cleared and re-set every 3 months.
Deer and takahē browse on the same tussock species in the Murchison Mountains. If left unchecked, the impact of high numbers of deer browsing can retard tussock growth and restrict the food and habitat available to takahē. In the 1970’s intensive deer control was introduced including helicopter hunting and the use of deer capture pens. Today deer control is undertaken by two commercial helicopter hunting operators.
Monitoring with Smart Transmitters
To help keep track of individual takahē and build-up a picture of what is happening to the wild population, about half the adult birds wear small ‘backpack’ smart transmitters. These transmitters send out radio signals which show a bird’s location and whether it is alive or dead or has dropped its transmitter.
The smart transmitters allow the birds to be monitored remotely via an aircraft fitted with a receiver (Sky RangerTM). The Fixed wing plane flies a grid pattern over the mountains carrying a Sky RangerTM GPS recorder, which logs the location and ‘state’ of each of the birds carrying a transmitter. Once back on the ground, the information is downloaded and assessed. This information is contributing to an on-going study of adult takahē survival in the Murchison Mountains.
2014 Murchison Mountains Takahē Survey
In November and December 2014, Takahē Recovery undertook a full survey of the takahē population in the Murchison Mountains. This was the first full survey in five years and allowed for the population estimates provided from the Sky RangerTM monitoring to be ‘ground-truthed’ to ensure they are providing an accurate picture of trends in the takahē population.
Small teams of DOC rangers searched the known territories for any sign of takahē. Mostly these are in basins and above the bushline, and at times travel between territories can be arduous. Luckily takahē leave lots of feeding sign and up to 6 metres of droppings per day, especially during spring when pairs are nesting and not moving about too much.
The good news. The results of the survey matched those of our Sky RangerTM flights.