Pest Bird Species
These birds are regarded as the most significant bird pests of the urban environment.
Their significance will vary from country to country and other species will, from time to time, cause problems in towns and cities.
The Feral Pigeon (Columba livia)
This is the number one urban pest bird throughout the world. Descended from birds which were originally domesticated for food, these birds have reverted to their wild state, but now live in close proximity to Man. Much loved by the general public, they are responsible for most of the bird-fouling of buildings and statues in towns and the transmission of bird diseases, such as ornithosis, to humans.
Scaring As no distress call has yet been isolated, scaring with auditory or visual systems is rarely successful for long.
Proofing Many systems are available, but great care must be taken with choice of bird proofing product for each part of the building. Bird netting with 50mm mesh is the most successful method.
Control Can be a good option for removing specific individuals; large-scale culling is rarely successful for long and incurs very significant adverse public reaction. Removal of food and shelter will help.
The House Sparrow (Passer domesticus)
This is a major problem for the food industry, with populations becoming established inside warehouse and retail premises. These "flying mice" gain entry through very small holes and then damage and foul stored food. They are extremely difficult to deal with and are now linked in NZ with salmonellosis, which is causing widespread deaths in the sparrow population (2001) This is of great significance for our domestic animals and primary industries by placing stock at greater risk from secondary salmonella infection and from infection of contaminated stock feeds.
Scaring No distress call has yet been isolated; scaring with auditory or visual systems is rarely successful for long.
Proofing Few systems are effective, due to the bird's small size and agility, with the exception of 19mm mesh bird netting.
Control Can be a good option for removing specific individuals; some methods require Special Licences e.g. to use avicides such as the narcotic Alphachloralose at high strength.
The Welcome Swallow, or House Swallow (Hirundo neoxena - Gould, 1842)
Rarely found in New Zealand before the late 1950’s, the Welcome Swallows now occur throughout the country. They were self-introduced from Australia. They usually build their cup-shaped nests on man-made structures. These include farm buildings, inside dairy milking sheds, in houses, inside culverts and on bridges. Nearly always nests are out of sunlight in weather protected positions. Swallows forage for flying insects catching them in flight. They are persistent residents wherever there’s shelter and abundant insect activity for food.
Proofing & Control This may need to be done with care. Initially try to relocate them by constantly pulling off their nests as they commence building them. The areas they decide to make home can sometimes be proofed by completely sloping off the ledges or window frames they want to use. The sloping material should be smooth and angled off to around 60 degrees to eliminate and toe-holds. Color-steel flashings folded to shape or sloped timber billets can be effective. On cold mornings before dawn, the application of cold water from a hose can be a further deterrent.
The Starling (Sturnus vulgaris)
This can be a major problem in certain localities and of no significance in others. The problem occurs when large numbers (can be tens of thousands) gather for night roosting. The noise, smell and extensive fouling caused by these congregations can be horrendous. Fungi associated with the dried guano can give rise to serious human disease problems.
Scaring This species has a distress call, recordings of which can often be used successfully to prevent night roosting.
Proofing Few systems are effective, due to the bird's small size and agility, with the exception of 28mm mesh bird netting.
Control Not usually a practical option, due to the sheer numbers of birds often present in the flocks.
Pukeko (Porphyrio melanotus - Temminck, 1820)
NZ has one of the 5 species recognised in Australia, and the South Pacific.
As land uses change, with open land being cleared or drained for farming, or building expansion in urban areas, the pukeko are losing their natural habitat. In some instances they come to be regarded as a agricultural or domestic garden pest. A ‘live and let live approach’ is commendable, especially where the problem may be from their loss of traditional habitats.
Proofing & Control Limited culling of pukeko is permitted in New Zealand. Ask your local DoC office on their requirements. Physical proofing measures are sometimes practical. Where they get into pools, fish ponds or gardens those may be able to be netted over. In home gardens, covering with professional grade BirdNet would be useful in minimising damage. Newly planted trees up to say, 400mm high can be planted inside Tree Guard protectors, to minimise loss.
Magpies are large birds growing to 16" or 40cm tall. They are widely distributed in rural areas and can become a nuisance in towns. They are territorial and tend to live in family groups.
Magpies are known for worrying other birds, taking their eggs and young, as well as frightening children with their swooping antics, particularly in the springtime breeding season. Occassionally it's reported that people have been injured. While they can be a nuisance in rural areas, they are efficient pest controllers, with a diet of many vertebrates such as porina, weevils, and caterpillars, and eggs of other birds and their young, as well as mice, seeds and grain.
Control Farmers have their own time-proven control methods which can also include using registered poison grain baits. Limitations are greater in towns and urban areas where cage traps and, magpie decoys to entice birds towards cage traps are more common
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The Common Myna (Acridotheres tristis - Linnaeus, 1766)
Mynas are a nuisance in houses getting under roofing to nest in eaves and roof cavities. Increasingly a nuisance in factories and warehousing which for any food related business, presents a great threat to food safety. They stoutly defend their territory & nest site against other mynas. As trees are removed in areas under development, they increasingly look to live inside buildings.
In rural areas they are also a crop pest, consuming pasture, the berries from nightshade and damaging other fruits including grapes. They will flock onto paddocks being ploughed and nest inside farm buildings. In New Zealand the Starling is the only other member of the same family.
Trapping New to the NZ market is the Myna Magnet cage trap. It’s a modern and humane approach towards minimising Myna numbers.
Poisoning Registered avicides are available containing a narcotic toxin for DIY use. However, at a stronger concentration of the active ingredient (alphachloralose) it should be used only by trained and licensed pest control technicians. To minimise risks of killing non-target native birds, the services of a pest control technician possessing a licence in alphachloralose use is recommended. Secondary poisoning is a risk to other hungry predators.
Proofing & Control For protection of buildings, physical proofing of the building exterior is recommended, perhaps in tandem with other bird reduction measures as above. Bird Brush is highly effective at blocking gaps around doors of all types. Ridge vents should be checked to ensure the wire mesh in the ridge is intact. Check also external openings such as broken glass, louvres and ventilation ducts, and holes left in walls when fittings have been removed. The edges of roofing may not have a barrier installed, which can often allow birds to enter under the roofing profiles. Open doorways may be the main bird entry point in warehousing and other stores, including farm buildings. PVC screens and door systems are available to minimise entry through frequently opened doors.
The Red Billed Gull (Larus novaehollandiae - Stephens, 1826)
Red Billed Gulls are well established throughout New Zealand. In towns and cities they are the most common gull. They can be seen scavenging on human refuse at landfills, and on wastes from food businesses, and in parks and places where people eat. They foul areas with their excreta on seating and walkways; on buildings, signage and lighting. By taking chicken bones and other wastes onto roofs, as the Black Billed Gulls do, they can block rainwater outlets in gutters, cause internal flooding and potentially transmit diseases through their excretal wastes and fouling.
Scaring This species has a distress call, but playing recordings of this back at the birds can have variable results.
Proofing A number of heavy-duty systems is available, with bird netting using 100mm mesh being the most successful.
Control Can be a good option for removing specific individuals; large-scale culling is rarely successful for long and incurs very significant adverse public reaction.
The Southern Black Backed Gull (Larus dominicanus - Lichtenstein, 1823)
The only large gull commonly found throughout New Zealand.
They cause a nuisance in cities and towns in parks and on buildings, and around coastal areas and ports. Gull excreta and nesting materials, and food scrap residues such as chicken bones, fish frames and shells they leave on roofs can block gutters causing internal water damage and produce foul odours and contamination risks from faecal contamination by perching and nesting around rooftop air conditioners. Walls and walkways beneath parapets often suffer excretal fouling. Can be very aggressive - to persons working on the roofs when nesting and, on farmland they will attack new-born lambs.
Scaring As with red billed gulls, scaring devices are not very effective.
Proofing & Control One of only two NZ native bird species without any level of protection under the Wildlife Act. They are sometimes shot, or poisoned using approved avicides. Eggs can be pricked. On buildings and other structures, electrified Hot Wire will deter perching, or use Bird Spikes on open & exposed parts of structures to prevent fouling or other damage to buildings.
It is essential to check on the legal status of these birds before action.
For further information on these New Zealand bird species refer to: www.nzbirdsonline.org.nz