The house sparrow was brought to New Zealand in 1867 to help farmers deal with crop-eating insects, but the small bird soon became a problem of its own.
asserted
bird → bring → own
Within a few years, while it grew in numbers, it also began damaging crops, leading farmers and authorities to turn against the species.
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it → grow → species
Introduce familiar European birds to New Zealand was not uncommon.
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Introduce → introduce → Zealand
According to government encyclopedia Teara, European settlers brought many bird species to the country.
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settlers → accord → country
Both because they missed the birds they knew from Britain and because they hoped some of them would help agriculture.
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some → miss → agriculture
In all, 130 bird species were brought to New Zealand, with 41 eventually establishing wild populations.
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41 → bring → populations
The Canterbury Acclimatisation Society liberated 40 sparrows in 1867.
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Society → liberate → 1867
The birds were expected to help control agricultural pests, particularly insects that were damaging crops.
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that → expect → crops
But sparrows did not remain focused on insects.
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sparrows → remain → insects
While they fed their young on caterpillars, beetles, flies and spiders during their first week after hatching, they were more interested in grains and fruit at other times.
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they → feed → times
That made the bird a serious concern for farmers.
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bird → make → farmers
Sparrows damaged wheat, barley and maize crops, and their ability to breed rapidly meant their numbers could rise quickly.
uncertain
numbers → damage → crops
The same qualities that made them attractive as a possible pest-control species eventually made them difficult to control.
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them → make → species
The introduction of birds gathered pace as farming expanded across New Zealand.
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farming → gather → Zealand
By the early 1850s, moths, caterpillars, beetles and grasshoppers had become major problems in agricultural areas.
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moths → become → areas
Some insect outbreaks were so large that they disrupted normal activity.
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they → disrupt → activity
Native birds did eat insects, but their ability to control pests in farmland was limited.
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ability → eat → farmland
They generally foraged in agricultural areas when nearby bush provided suitable habitat.
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bush → forage → habitat
As more land was cleared for farming, the bush edge was pushed back and native birds had even less influence on farmland pest populations.
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birds → clear → populations
Farmers therefore looked towards birds from Europe.
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Farmers → look → Europe
Species such as blackbirds, thrushes, starlings, sparrows and magpies were introduced in the hope that they would eat insects and reduce crop damage.
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they → introduce → damage
From the 1860s, acclimatisation societies began organising these introductions more systematically.
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societies → begin → introductions
They selected birds partly for their ability to survive in New Zealand and reproduce in large numbers.
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They → select → numbers
Some societies also wanted birds that could eat insects during summer but switch to other food, such as seeds or grain, during winter.
uncertain
that → want → winter
Sparrows' rapid rise led to organised efforts to control them.
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rise → lead → them
The sparrow boom
As few as 100 house sparrows were liberated in New Zealand between 1866 and 1871, while the Canterbury Acclimatisation Society released 40 in 1867.
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Society → liberate → 1867
Te Ara says this was probably helped by abundant food, little competition, a mild climate and few predators at the time.
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this → say → time
Early observers noticed that female sparrows could lay another clutch of eggs while their previous young were still in the nest.
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young → notice → nest
The young birds apparently helped incubate the eggs.
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birds → help → eggs
Naturalist Thomas Kirk highlighted the potential scale of this growth in 1878.
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Kirk → highlight → 1878
He calculated that one pair of house sparrows could theoretically produce a population of 322,000 within five years.
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pair → calculate → years
A new pest emerges
The introduction of the house sparrow was intended to reduce insect pests, but the birds themselves began to be seen as a threat to agriculture.
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birds → emerge → agriculture
The problem was not limited to sparrows, however.
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problem → limit → sparrows
Other introduced small birds also multiplied and damaged crops.
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birds → introduce → crops
Sparrow clubs were formed in the 1880s to reduce what was described as the 'sparrow plague'.
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what → form → plague
The clubs were modelled on similar organisations established in England from the 1850s.
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clubs → model → 1850s
The methods included poisoned grain, shooting and financial rewards for collecting sparrow eggs.
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methods → include → eggs
Bounties were also offered for eggs and heads of small introduced birds.
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Bounties → offer → birds
The system encouraged children to collect sparrow eggs, with small boys gathering hundreds of thousands of them.
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boys → encourage → them
The Aporia
