Bird buildup worries Christchurch airport
The number and variety of pest birds on Christchurch's lower-level flight paths is increasing, an airport representative has told city planners.
Bird-strike is a reason for limiting commercial and residential development in its flight area under a revised city plan, Christchurch Airport says.
Airport (CIAL) legal counsel Jo Appleyard said it was "critical that CIAL is protected against inappropriate development in the vicinity of the airport, including residential development under the 50 decibel noise contour, bird-strike risk activities" and other risky activities for flight-related safety.
"Of particular concern to CIAL in recent times is the steady increase in ... pest bird species in the northwest and west sectors of Christchurch," Appleyard told an independent hearing panel.
Species which threatened aircraft included various gull species, Canada Geese, introduced and indigenous water spurwinged plover and magpies, Appleyard said.
With the "alarming increase" in Canada Geese numbers, more attention has been given to bird numbers and bird movement on the Waimakariri River, Brooklands Lagoon, Travis Swamp, the Avon, Heathcote, estuary, Rotokohatu twin lakes, the Groynes, Clearwater Resort and Styx Mill Reserve, she said.
Birds had been observed flying to and from Travis Wetland, the estuary and Brooklands, in and over the city to Ellesmere to the west and north-west of the airport. They had also been seen flying to the Styx Mill/Groynes/Waimakariri areas in the morning - before and after sunrise - and in the evening about and after sunset.
A growing number of Canada Geese building up on Lake Ellesmere/Te Waihora had been seen flying north-south to the west of the airport.
The airport was a regular participant in planning processes involving the potential creation of water bodies or other bird habitats. The airport company had "been forced" to attend a number of plan change hearings for the Christchurch, Selwyn and Waimakariri districts to ensure the councils had "adequate bird-strike risk management provisions", she said.
The airport wanted to avoid another process like this in Christchurch by creating bird-strike regulations in the city plan, Appleyard said.
The risk of bird-strike was like the airport's 50 decibel noise contour (maximum) for Christchurch and other areas within lower-level airport flights paths.
Managing bird-strike could be controlled in the replacement district plan in the same way. Over time, aircraft had become too quick and too quiet for birds to sense and avoid, she said.
"Birds inadvertently became a serious threat to aircraft safety as strikes became more frequent and more serious, warranting the need for increased bird management around airports."
Birds were attracted to areas around the airport for a number of reasons, including food sources, surface water and suitable habitat.
The risk of bird strike would increase with the creation of water bodies, refuse dumps, landfills, sewage treatment and disposal, as well as agricultural activities.
All would "clearly affect the ability of CIAL to provide (a) safe environment".
The airport was already heavily involved in bird management around the airport, including a "wildlife management programme", active monitoring and shooting. Its methods included bird-scaring devices and "active pasture management," Appleyard said.