Anti-bird spikes, also known as bird spikes or pigeon spikes, are devices used to deter birds from landing and nesting on certain surfaces. They consist of thin, spike-like strips or coils of stainless steel, nylon, polycarbonate or other materials that are attached to ledges, rooftops, signs and other areas birds tend to frequent. The spikes act as a physical barrier that makes it difficult for birds to gain stable footing on the surface, forcing them to look elsewhere to roost or build nests.
Do birds nest with anti-bird spikes?
Most birds will avoid areas with properly installed anti-bird spikes and look for alternative nesting sites. However, there are some determined bird species that have been known to occasionally build nests incorporating the spikes themselves.
Birds that create cup-shaped nests in small spaces, such as pigeons, sparrows, and swallows, generally have the easiest time overcoming anti-bird spikes. By gathering twigs and grass to build up a base, these birds can create a nest that sits securely on top of the spikes. The nest materials help separate the eggs and chicks from the spikes below.
Here are some examples of birds known to occasionally nest on anti-bird spikes:
Pigeons
Pigeons are resourceful urban birds that can construct nests in the smallest of spaces. They have been observed building nests on top of bird spikes using scrap materials like twigs, grass, paper, and trash.
House Sparrows
Sparrows are also habitual nesters that have adapted to urban environments. If no better nesting sites are available, House Sparrows may stubbornly build nests incorporating anti-bird spikes.
Barn Swallows
Barn Swallows frequently nest on vertical surfaces under overhangs and eaves. They have been seen building mud nests on bird spikes when suitable sheltered sites are limited.
European Starlings
Like House Sparrows, European Starlings are tenacious birds that will nest in challenging spaces. Starling nests on spikes may consist of straw, grass, litter, or other debris.
Common Grackles
Grackles have sturdy beaks that can be used to weave nest materials like twigs through anti-bird spikes. Their large nests can sometimes engulf the spikes.
Cliff Swallows
The mud nests of Cliff Swallows have occasionally been observed affixed to vertical or inverted surfaces covered in bird spikes. They may incorporate the spikes into nest walls for additional support.
Why birds nest on anti-bird spikes
There are a few key reasons why certain birds are motivated to build nests directly on bird spike deterrents:
Lack of better alternatives
When suitable nesting sites are scarce, birds may be forced to get creative and build nests on less than ideal surfaces like anti-bird spikes. They are opportunistic nesters by nature.
Shelter and protection
Building nests on spikes attached to walls or ceilings can provide birds with an elevated, sheltered location protected from weather and terrestrial predators.
Determination to nest
Some birds exhibit strong nesting instincts and persistence that override the challenges posed by anti-bird spikes. They may engage in trial-and-error building until achieving a stable nest.
Adaptability
Birds like pigeons and sparrows that thrive around human structures have adapted to incorporate artificial materials into their nest building strategies. They can improvise with what’s available.
Preventing birds from nesting on anti-bird spikes
While not completely foolproof, there are some tips that can reduce the likelihood of birds building nests on bird spike deterrents:
Ensure proper installation
Gaps should not exist between spikes. The strips or coils should be securely affixed to the surface according to manufacturer specifications, with spikes spaced 2-4 inches apart.
Use taller spikes for problem areas
Longer spikes measuring 5 inches or taller leave less open space for birds to nest on. However, ensure they do not pose risks to people underneath.
Combine spikes with other deterrents
Using bird spikes along with other techniques like repellent gels, predator decoys or noise devices can discourage nesting more effectively than spikes alone.
Promptly remove any nest materials
To prevent nest completion, inspect often and remove any items birds have dropped between spikes or built on top. Persistence is key.
Install angled spikes on ledges
Pointing spikes at an inward angle of 30-45 degrees can make it more challenging for birds to land and gain footing.
Use flexible spike strips for irregular surfaces
Pliable spike strips that can conform to curves and bumps leave fewer gaps for nest access compared to spike mats or coils.
Example bird nests on anti-bird spikes
Here are some examples of how birds can construct nests to override anti-bird spike deterrents:
| Bird Species | Nest Description |
|---|---|
| Pigeons | Nests built with twigs and debris placed between and on top of spikes attached to building ledges. |
| House Sparrows | Scrappy nests woven into spikes on structures. Materials may include grass, paper, and litter. |
| Barn Swallows | Mud nest structures affixed onto vertical or inverted spikes, often under overhangs. |
| European Starlings | Twig and straw nests situated on top of spike coils or strips affixed to building crevices. |
| Common Grackles | Large, tangled stick nests built on spikes by weaving materials through. May cover spikes completely. |
Conclusion
Anti-bird spikes can be circumvented by highly motivated and adaptive species like pigeons, sparrows, swallows and starlings when preferred nesting locations are unavailable. However, proper installation and maintenance of spikes, plus combining them with other deterrents, can reduce instances of birds nesting directly on top of the spikes in most situations.
Whenever spikes are used, it’s important to monitor them closely for any nesting attempts and remove materials promptly to prevent completion of nests. While a bit of clever persistence allows some birds to overcome anti-bird spikes, proactive maintenance can help preserve the effectiveness of spikes and discourage nesting where they are installed.
