Story: Land birds – overview
Page 5 – Habitats: introduced and native land birds
Birds of town and farmland
New Zealand is unusual in that most of the birds in the cities, towns and farmlands have been brought from some other part of the world. In comparison, most of the birds in Australia or any European or American country are native, even in the largest cities.
The Pākehā settlers who came to New Zealand enthusiastically brought many plant and animal species. Acclimatisation Societies were formed to introduce useful or ornamental animals, birds, fish and plants.
A reminder of home
Most introduced species came with settlers from Britain, but a few have been brought from elsewhere. Among the land birds the magpie (Gymnorhina tibicen) was introduced from Australia, the Californian quail (Callipepla californica) from the USA, and the chukor (Alectoris chukar) and common mynah (Acridotheres tristis) from Asia.
Today the most common and widespread land birds in towns and farmland, including house sparrows, blackbirds, starlings and various finches, are introduced.
The common silvereye and welcome swallow have colonised New Zealand since Pākehā settlement created habitats that suited them. These are considered native because they arrived unassisted.
Native birds still rule the forests
Introduced species are far less common in indigenous forests, where native birds prevail. On mammal-free islands with relatively intact native forest habitats, silvereyes, swallows and introduced species are rare. Because the native and introduced birds are adapted to such different habitats, introduced birds have apparently had little direct effect on the native species.
Karori Sanctuary in Wellington has a 250-hectare pest-free reserve bounded by a high fence that keeps out all introduced mammals except mice. Native birds have increased their numbers and endangered species such as little spotted kiwi and saddlebacks have been released there.
Few native birds in cities
Only a handful of native land birds can survive in towns and cities. Even on farmland few remain unless large enough remnants of native forest or scrubland are saved. The fantail, silvereye, grey warbler, bellbird, tūī and kererū are the most adaptable native land birds. At least some of these species are in towns and on farmland where there are still suitable introduced or native tree areas and food sources. They will also return to areas where native bush is replanted.
Why are so few native land birds found in towns and farms? They evolved in unique forest habitats that were very different from today’s urban and rural environments. They were ill-adapted to cope with the dramatic habitat changes, including the rats and cats that are so numerous where people live.