'Judas' goat with a radio transmitter around its neck, used in goat control
Goat browse on unfenced vegetation plot
Feral goat herd, Great Barrier Island
Goats were introduced to New Zealand in the early days of European settlement for food, to estabish a commercial fibre industry, and for weed control on developing land. The descendents of those that escaped or were deliberately released thrived in the country’s grass hills, forest and scrubland areas.
Today feral goats (Capra hircus) occur on both main islands and a few offshore islands. Feral goats are classifed as wild animals under the Wild Animal Control Act 1977.
Colour wise, they can be white, brown or black, or any combination of these. In New Zealand both sexes have horns. All males and some females are bearded as adults. Males are the largest sex, with clearly heavier forequarters, shaggier coats and larger horns.
Where are they found?
Feral goats are found in a wide range of habitats. They range from sea level to the alpine zone, living in introduced and native grasslands, scrub and forest.
Because they are browsers, their preferred habitat is forest or scrub-covered upland containing areas of grassland. They are agile on steep crags and narrow ledges and can get to areas that deer can not reach. They like sunny sides of slopes, making use of open places close to the shelter of forest or scrub.
Why are they here?
Goats arrived here as early as 1773, when Captain James Cook released them ashore in the Marlborough Sounds during his second voyage to New Zealand. Early explorers, whalers, sealers and settlers bought goats with them for food, and used them to barter with Māori.
During the late nineteenth - early twentieth century, goats were released onto outlying islands to provide a food source for castaways. Angora goats were introduced about the same time to develop an industry for their fine wool, which never really took off.
As land around the country was ‘developed’, weeds such as gorse, blackberry and briar invaded and goats were brought in to eat the weeds.
Feral goats now occupy about 14% of New Zealand - about half of this on public conservation land. Total population size is unknown but is estimated to be several hundred thousand.
New Zealand’s native plants are particularly vulnerable to damage from browsing. Herding browsers such as goats cause two-fold damage by eating native plants and by trampling large areas of vegetation and compactable soils.
Goats will eat the foliage of most trees and plants and quickly destroy all vegetation within their reach, eating seedlings, saplings and litter-fall off the forest floor. They do however have strong preferences and will eat out favoured species first such as broadleaf/pāpāuma (Griselinia littoralis) and māhoe (Melicytus ramiflorus) before moving on to less desirable plants. Goats will also strip bark off trees and by eating young seedlings they effectively put a stop to forest regeneration.
Government control operations of feral goats began in the 1930s in areas where goats competed with sheep for available grazing. These days, goat control is targeted at areas where their browsing threatens rare native plants or damages the forest understorey.
Goat control operations today are based on the values at each site, feasibility of control/eradication and other conservation management activities happening at the site.
In open country, with low population densities, Judas goat technology is sometimes used. In these situations, a goat is caught, fitted with a radio-collar and released back into the area. This animal - known as a Judas - then hopefully joins up with any remaining mob of goats, allowing the hunter to locate and shoot the mob.
You can help
Signs goats are present
Tracks show paired hooves with pointed, slightly incurved tips, just like sheep tracks. Faecal pellets can be found singly or in groups and are smooth, an elongated oval shape, rounded at each end – very similar to sheep, sika deer and possums.
The call is a 'meh' rather than a 'baa' (sheep) and rutting males have a pungent smell.1
If you are planning a pest control operation enrol for the Animal Pest Control Methods field based course.
The course provides an overview of animal pests, their impacts and control methods (including the principles these are based on, and the task specifications DOC has developed).
The course covers all the legal requirements for animal welfare and handling toxins. Working within the law is vital to allow pest control agencies and community groups continued access to the full suite of animal pest control methods.
In particular, it describes the control methods most commonly used in DOC, and their advantages and disadvantages.