Pest Birds in New Zealand

  • There are a number of pest birds in New Zealand primarily introduced species such as the pigeon, sparrow, starling and Indian Myna. Amongst the native birds, the silver backed gull and welcome swallow can be significant pests.
  • Some species of birds are significant pest in agriculture and food storage areas where they damage crops and spoil foods.
  • Around buildings, birds cause noise pollution, make a mess with their droppings and damaging buildings. A recent problem is the damage they cause to solar panels.
  • Birds carry a range of parasites and diseases which can be a significant health threat to humans.

Birds can be significant pests in agricultural, commercial and residential settings. There are six aspects to their pest status:

  1. Damage to crops: Damage to seed crops and soft fruits can be significant, especially with large flocks of starlings and sparrows
  2. Spoiling stored product / food: In rural areas bird may target areas of grain storage and animal feed,  but they will target any food manufacturing / service facility
  3. Noise: Roosting birds in large numbers can cause significant noise pollution – starlings are the most common culprit
  4. Damage to buildings and other surfaces: Bird droppings are acidic and will damage a wide variety of surfaces if left for any length of time
  5. Solar panel damage: Birds nesting and resting around solar panels can cause a significant drop in panel efficiency with their mess and can cause lasting damage to the panels
  6. Slip hazard: It may sound a bit silly, but bird roosting and nesting on buildings can deposit a large amount of droppings on the ground below, causing a significant slip hazard
  7. Health hazard: Bird carry a wide range of parasites and diseases that can be passed on directly or through their droppings

Pigeons have been found to carry more than 110 pathogens. Some of these are airborne diseases, such as Chlamydia psittaci (ornithosis) and Cryptococcus neoformans, and others are food-borne diseases, such as Salmonella, E. coli and Listeria.

The danger of potential transfer through contact with visible droppings and seeing birds walk across surfaces may be obvious, but the more sinister dangers are the airborne diseases. The risk of picking up an airborne disease occurs when the droppings dry out. The risk increases significantly when entering areas with a bird infestation or carrying out removal and clean-up work. It is critical to minimise the risk of disease transfer by wearing suitable safety equipment; spraying droppings with water prior to clean-up to minimise aerosolization; using cleaning equipment with HEPA filters; and bagging waste.

The risks of disease transfer are very real. The British Pest Control Association (BPCA) reports that, “Research suggests that up to 49% of feral pigeons could be infected with Chlamydia psittaci.” People who become infected are diagnosed with ornithosis, with symptoms including chills, fever, sweating, severe weakness, headache, blurred vision, pneumonia, and possibly death.

But it’s not only ornithosis that should be cause for concern. According to the BPCA, “In 2019, two patients died in a Glasgow hospital who had contracted a cryptococcal fungal infection, which was subsequently linked to pigeon droppings.”

Bird infestations are not only annoying, they present a very real health hazard.

Birds carry a number of internal parasites, such as tapworms and protozoa (Giardia), and also external parasites, such as fleas, ticks and mites. It is the bird mite that can cause issues for humans, invading the rooms underneath the roof void where birds are nesting.

Bird mites are a common bird parasite feeding on adult and young birds in the nest. When the young birds leave the nest or die, many mites (often many tens of thousands) are left behind in the absence of a suitable host, and these will disperse from the nest into and throughout the dwelling searching for new hosts. Most mites will die within three weeks without a blood meal from a bird host. However, they will bite humans they encounter, although they cannot survive on humans.

As a result of their ‘test biting’ while searching for a new bird host, the mites inject saliva. Although bird mites are not associated with the transmission of any infectious disease, the bites can lead to severe irritation with rashes and intense itching. Scratching of the bites may result in secondary infections. The bites are often difficult to diagnose and can be mistaken for bites from a number of other arthropods.

Before dealing with a bird problem is it essential to wear a mask with particulate filter, gloves, boots and overalls.

Dead birds should be picked wearing disposal latex gloves and placed in a plastic page along with any nesting material. This sealed back should be placed in a further sealed bag before disposing in a garbage bin.

If there is only a small amount of bird mess, it should be sprayed with disinfectant before wiping up with towels and placing in a plastic bag which should be sealed before disposing. Spray the area again with disinfectant after the mess has been removed.

Wash hands and overalls thoroughly.

For larger amounts of mess, your professional pest manager may also clear it up, as part of their bird management services. However, even for pest managers, especially where there is significant amounts of bird mess, it may be necessary to hire a specialist, commercial cleaning company.

DO NOT brush or vacuum up the material – it causes disease carrying particles to go airborne.

Culling birds generally only occurs as a last resort, most professional bird management is focused on the excluding or repelling birds from the area in question.

Excluding birds from roosting or resting on ledges is normally achieved with bird spikes, although “slopes” or electrical tracks can be used as alternatives. There are new repellent gel products (which mimic fire) that can also be used.

To exclude birds from areas, netting is normally the only viable option.

Visual or sound repellents can be considered for areas that cannot be protected using the products described above.

Bird proofing solar panels is becoming an essential requirement for homeowners and business owners, to protect the panels from damage and ensure optimal electrical output. The area under solar panels provide an ideal, protected nesting area. Installation of an exclusion skirt around the base of the panels will prevent the birds nesting.

Professional pest managers will often provide solar panel cleaning services at the time of installation and on an annual basis if required.

Sometimes additional bird protection measures may be required if the roof itself becomes a bird roosting site.

To prevent birds nesting at your home it is important to eliminate potential nesting sites. Primarily this means prevent access to the roof void and excluding birds accessing the area underneath any solar panels.

Welcome swallows will build their mud nests under the eaves of homes. If you spot the swallows starting to building their nests, you need to act immediately, as once the nest has been built and the eggs laid, you cannot remove the nest as they are a native animal.

If birds are roosting in your area, it is important to minimise any food sources – grain and animal feed should not be left on the ground. However, if birds do take a liking to roosting on your roof, you will need to get professional help to exclude them.

Our pest control library has more information on pest control birds.