Poison not the answer to feral pigeon issue
Dummy eggs are another method being considered by Gisborne District Council as it struggles with high feral pigeon numbers in the central business district.
The council attracted national publicity in May when it decided to trial using recreational shooters to cull the pigeon population on their feeding grounds.
The action came after inner city resident Richard Jackson called for a major cull of the pigeons and said the problem was so bad that the council, not building owners, should assume responsibility.
The trial has gone ahead but in a recent report to the environmental planning and regulations committee, council biosecurity team leader Phil Karaitiana suggested a mixed approach that would include shooting, dummy eggs and mechanical methods such as wires or nets to keep the pigeons away from their favoured sites.
Dummy eggs involved placing pigeon lofts on city centre buildings from which fertile eggs laid would be removed and replaced by dummy ones.
The method had been used overseas and in some instances had proved successful in reducing populations, said Mr Karaitiana.
Recent scientific research, however, suggests egg removal results in birds merely increasing the frequency of reproduction to offset the impact.
The research also notes it is a costly exercise.
Mr Karaitiana said the success of the shooting trial would depend on the frequency of shooter activity over the winter months.
It was expected there would be an increase in shooter activity in spring and summer.
There were two licensed shooters involved in the programme with further interest expected in the early spring.
The best option to control the pigeons was to continue the use of shooters, undertake a trial using dummy eggs in breeding lofts in the city centre and trial mechanical exclusion methods.
Mr Karaitiana did not recommend the use of a toxin or poison because an initial knockdown would only be a temporary fix.
Pigeons on the outskirts of the poisoned area would quickly occupy the vacant sites and carry on breeding. The population would rapidly expand.
He said the use of toxins was open to public concern, criticism and potential risks.
Non-target species were also exposed indirectly.
A recent situation where the application of the toxin by a city resident to control nuisance sparrows clearly demonstrated the effect of the toxin and led to concerns by residents in the vicinity of the poisoning.
Mr Karaitiana said buildings and bridges provided an ideal habitat for pigeons to occupy all year round. Pigeons under bridges were difficult to remove unless they were culled by shooting.
Phoenix palm trees scattered around the city and wider community were another habitat for large pigeon populations.
There had been progressive removal of Phoenix palm trees in the city area but that had resulted in pigeons increasingly using CBD buildings as roosts.