Non-native birds are undervalued in New Zealand, writes Stephen D Wratten.
New Zealand has an audacious plan to protect its native birds. The country has pledged to rid itself of introduced mammalian predators by 2050 and, this year, will spend $20 million on the Battle for the Birds, one of the largest predator control programmes in the country's history, across more than 800,000ha of land.
Of the 168 bird species native to New Zealand, four in five are in trouble, according to a report published last month by the Parliamentary Commissioner for the Environment. New Zealand's native birds deserve help, but several introduced bird species are also disappearing.
The early settlers brought 130 bird species to New Zealand, and 41 of them established. Given that in lowland areas in Canterbury, for example, less than 1% of the original biodiversity remains, perhaps we should place greater value on non-native biodiversity.
Not everybody agrees with the value of non-native birds. In 1883, resistance leader Te Whiti wrote: ''It was not good work bringing those birds out here; they eat all the potatoes and the oats; they are not good birds to bring out ... were there not plenty of good birds in New Zealand that eat no man's food?''
A key recent development, however, which appears to be raising awareness of the value of introduced birds is The New Zealand Garden Bird Survey, organised by Eric Spurr, of Landcare Research. After a decade, results show at least six non-native species - starling, song thrush, blackbird, goldfinch, chaffinch, and dunnock - have declined since the survey started.
The counts are only of birds in gardens, and the reasons for the declines have not been determined, but the picture is beginning to mirror the dramatic declines in bird populations in Europe during the past 40 years. These include the common starling and the skylark.
In Europe, these birds have played an enormous part in art, poetry and literature for hundreds of years. One is reminded of the poem The Lark Ascending by Meredith, and Vaughan Williams' music on the same theme. In art, birds such as the goldfinch have featured in work by Fabritius and Tiepolo, and throughout the Renaissance period this bird's blood-red face and its habit of feeding on thorny thistles led to its association with Christ on the cross. The Beatles sang a song called Blackbird, in 1968.
In New Zealand, introduced bird species do not generate the affection of endemic ones, such as the tui. In Canterbury, flocks of rooks, a key part of the English countryside, were common, but they have been poisoned and shot almost to extinction.
Recently, Lincoln University colleagues wrote a report for the Department of Conservation about the contribution of native ecosystems to New Zealanders' mental health. However, we can't ignore the contribution our non-native flora and fauna make to our sense of place and wellbeing.
It is possible the contribution which introduced bird species make to New Zealand is also delivering other ecosystem functions and services. They eat weed seeds and pest insects, pollinate native shrubs and trees and distribute seeds of plants, just as our endemic birds used to do before their numbers were drastically reduced by introduced predator fauna.
In Britain, urbanisation, fragmentation of the countryside and intensification of agriculture are being associated with these huge losses. In New Zealand, there have been dramatic changes in the farming landscape.
Male skylarks used to sing in the sky above my house when we were surrounded by low-intensity farming, but now I see and hear virtually none. We are beginning to lose our under-valued introduced bird species and this should be a cause for concern.
-theconversation.com/au
-Stephen D Wratten is professor of ecology at Lincoln University.
