A Complete Guide To Bird Pests

Birds might seem harmless, beautiful and even majestic out there in the wild, but they can be a real nuisance when they invade your property.

Although they are not directly harmful to humans (mostly) and will generally coexist peacefully with us, they can cause a lot of problems when present in large numbers near human inhabitations. It is these problems caused by birds that make us forget their beauty and splendour and regard them as pests that need to dealt with.

Here’s what to look out for.

A number of problems are associated with an avian infestation. Here are the major ones:

1. Property damage. Birds will damage your property with these two things:

  • Droppings – Bird droppings cause the most damage to property mostly due to the uric acid (of pH 3 – 3.5) it contains which corrodes numerous materials including steel, paint, and stone. Birds will also plaster the area they infest with guano causing the structure or building to lose its aesthetic value.
  • Nests – Birds will construct nests on your property for shelter using grass and straw. These nests can clog gutters and roof drainage resulting in a damaged roof. Nests constructed in vents will also hinder air circulation in buildings while those constructed near electrical installations pose a potential fire hazard.

2. Health risks – Bird droppings contain bacteria and fungi that when introduced to the human body through inhalation or ingestion could cause serious illnesses.

3. Noise – Birds are very noisy when they gather in large numbers which could make for less than ideal working conditions as well as interrupt other activities.

4. Accidents – Fresh bird poop is very slippery and could cause slip and fall accidents that could result in serious injuries. Accidents in your business premises could also expose your business to liability suits that could prove costly.

5. Food damage and contamination – When they invade farms, warehouses and food stores, birds will contaminate and destroy food making it unfit for consumption.

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Bird pests common in New Zealand

Some of the common bird pests in the country include:

  1. Feral pigeons or Columba liva – Once domesticated for food, these birds later turned wild and have increased in population and now account for most of the bird-fouling of buildings and statues today.
  2. Red-billed Gull – These are large and aggressive birds mostly found in coastal towns and cities. The noise, mess, and smell they bring to the areas they inhabit make them a great nuisance.
  3. Sparrows – Nicknamed the “flying mice” these birds cause a lot of damage to stored food. They also pose a big health risk as they contaminate food for both humans and livestock.
  4. Starlings – These have a tendency to gather in large numbers and build nests in roofs and eaves. They bring dirt, odour and noise to the buildings they infest.

The life cycle of a bird

Shortly after fertilisation, the female bird identifies a place where she can lay her eggs – depending on the species, this will either be in a nest or a hole in the ground. A great number of birds prefer to build nests shaped like plates, mounds or domes to live and breed in.

The eggs require to maintained at a certain temperature (or incubated) for them to develop. Incubation begins immediately after the female bird lays her last egg and will last until the final one hatches.

Incubation duties are shared between the two parents in monogamous species while one parent takes the responsibility in species that practise polygamy. The warmth passes from the bird to the eggs through patches of bare skin on the bird’s breast and abdomen called “brood patches”. The eggs will take between 10-80 days to hatch depending on the species.

Chicks are either brought up by a single parent or both in polygamous and monogamous species respectively.

Controlling birds

Prevention is the first step for controlling any pest and birds are no exception. Like most pests, birds are attracted to your property by food. Make sure you dispose of your garbage in covered bins and that there is no food littered on your property.

Although getting rid of food sources around your property is a good way of reducing the chances of a bird infestation, birds could still invade your property requiring more targeted control methods.

Because of their importance to the ecosystem (and sometimes legislation), only humane bird control methods that don’t harm the birds can be used to keep them at bay. The most used include bird control spikes and bird repellers that use audio, visual or physical stimuli to scare away birds.

Bird control spikes

Bird spikes are a very effective, humane bird deterrent, also called roost modifications, anti-roosting spikes or simply bird spikes. They can either be made using UV resistant polycarbonates, stainless steel, or a combination of the two materials. Bird spikes consist of upward projecting rods (or spikes) attached to a solid base.


Anti-roosting spikes prevent bird infestations by making it impossible for birds to land on buildings and structures. The length and density of the spikes are determined by the size of the bird you want to protect your property against with larger birds requiring long sparsely packed spikes and vice versa for smaller birds.

Bird spikes can be used to protect street lighting, building ledges, pipes, commercial signage, roof apex among other bird roosting sites.


Bird spikes are very simple devices which makes them pretty easy to install. For spikes with a polycarbonate base, specialised adhesive is used to attach them to the structure to be protected while fasteners are used for bird spikes with a steel base.

Benefits of using bird spikes

Using bird spikes for controlling birds is beneficial in the following ways:

  1.  Discreetness – Bird spikes are very hard to see from a distance which makes them good at preserving the aesthetic of the protected building or structure.
  2. Easy installation – Because they are not complicated devices, installing them is quite straightforward and can be done by the user.
  3. Low maintenance – Bird spikes require minimum maintenance once they have been installed. All you need to do is check periodically whether they have come undone.
  4. Humane solution – Bird spikes do not cause any harm to the birds they are protecting against.

Read about our bird spikes >

Other bird repellers and deterrents

Although bird spikes are very effective, they are mostly limited in the areas they can be used which mainly consist of buildings and structures. Other repellers and deterrents for other situations include: Sound repellers


These use either ultrasonic sound (inaudible to humans) or “normal” audible sound to scare away invading birds. The devices either use motion triggers for activation when birds come around or go off at a set time interval.
Ultrasonic bird repellers produce a high-frequency sound ranging between 15kHz and 25kHz. This high-frequency sound is inaudible by humans but disorients, confuses and intimidates birds. Other than making them uncomfortable, the sound does not harm the birds.


These devices are designed to be weatherproof because they are meant for outdoor use. A combination of solar and rechargeable batteries is used to power them so that they can work without the need to plug them into a power source.

Sound repellers are good for protecting large outdoor spaces such as marinas, farms, gardens, orchards, and yards. Audible sound repellers are limited for use in areas where short bursts of loud noises can be tolerated.

Installing bird sound repellers is easy and does not require any technical knowledge or skills. Just position the device in a good location with access to sunlight and you are done.

Benefits of using sound repellers

These are:

  1. Protection for large areas – Sound can travel for quite a long distance which makes these repellers ideal for protecting expansive areas such as orchards and farms.
  2. Easy installation and use – Sound repellers are easy to install and use. They require very little user intervention after the initial setup.
  3. Additional protection from other pests –These repellers will also scare away other intruding pests such as feral cats, dogs, and possums.
  4. Round the clock protection – Because they have batteries, sound repellers although reliant on solar will work effectively even at night.

Read about our audible bird repellers >

Visual deterrents

These exploit the birds’ eyesight to frighten them. Some resemble predatory birds like owls, others human beings, while others – like holographic tapes – reflect light dramatically to a scare birds off your property.


Visual deterrents can be used to protect beaches, ponds, balconies, farms, and gardens. Because they need to be seen, visual deterrents are not effective after the sun goes down.

As for installation, no special skills or equipment are required to install them and can be done DIY style.

Benefits of using visual deterrents

Visual deterrents are:

  1. Quiet – These deterrents unlike sound repellers don’t emit any sound and are ideal for places where silence is required.
  2. Humane – Visual deterrents are humane and don’t cause any harm to the birds.
  3. Low maintenance – After you have installed them, visual deterrents don’t require any other alteration; just a periodic check to see if they are still in place.
  4. Cheap – These are cheap to buy and install.

Read about our visual bird repellers >

Physical repellers

This kind of repellers use a physical medium like a water jet to startle birds off your property. Similar to sound repellers, these also rely on motion detectors for activation and use a combination of solar and rechargeable batteries.


(A water jet bird repeller)

They work well for small areas such as vegetable patches and yards. Some like those that use a water jet are limited to areas where moisture is not a problem.

These bird deterrents are designed for consumer use and will therefore not require specialised skill to install.

Benefits of using physical repellers

Physical repellers are:

  1. Environmentally friendly – Physical repellers don’t use or emit any substances that could harm the environment.
  2. Safe – These are safe for humans pets and the birds they are scaring away.
  3. Effective –  A deterrent that “touches” the bird is more effective than those that don’t.
  4. Good at keeping other intruders away – A physical deterrent will be set off by any other intruding animal making them quite good for broad pest control.

Read about our physical bird repellers >

Each of these options will only work well if deployed in a suitable situation. Analyse carefully the area or property you want to protect before settling on one to ensure that the control method you select is effective for that particular circumstance.

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