Cell towers provide convenient nesting sites for many bird species due to their height and structural support. Birds that build nests on cell towers include several raptor species, corvids, swallows, and some songbirds. The use of cell towers as nesting sites by birds can cause issues for cell tower maintenance and function, so understanding what species nest on towers can help inform management strategies.
Raptors that nest on cell towers
Many raptor species are attracted to cell towers as nesting sites due to the height advantage they provide for hunting and as a relatively isolated and predator-free location to raise young. Some raptor species known to nest on cell towers include:
- Red-tailed Hawks
- Swainson’s Hawks
- Ferruginous Hawks
- Harris’s Hawks
- Red-shouldered Hawks
- Great Horned Owls
- American Kestrels
- Peregrine Falcons
- Bald Eagles
- Ospreys
These raptor species often build large stick nests on platforms near the tops of towers. The height of the nests provides good visibility and easier take-off and landing when hunting. Cell towers in open habitats like grasslands, deserts, and wetlands tend to attract the highest diversity of nesting raptors.
Corvids that nest on cell towers
Members of the corvid family like crows, ravens, magpies, and jays also construct nests on cell towers. Species known to use cell towers include:
- American Crows
- Common Ravens
- Black-billed Magpies
- Yellow-billed Magpies
- Blue Jays
- Steller’s Jays
Corvids build large, basket-like stick nests on towers, typically below the nests of raptors when both occur on the same tower. They take advantage of the aerial protection from predators that raptor nests provide. In some cases, cell tower nests may allow corvids to expand their range into areas that lack natural nesting sites.
Swallows that nest on cell towers
Many species of swallows frequently nest on cell towers, including:
- Barn Swallows
- Cliff Swallows
- Cave Swallows
- Violet-green Swallows
- Tree Swallows
- Northern Rough-winged Swallows
Swallows build mud nests attached to vertical and horizontal surfaces on towers. Nesting colonies can sometimes number in the dozens or hundreds of pairs. Cell towers provide swallows with artificial nesting substrate similar to the cliffs, caves, and crevices they nest on naturally.
Other birds that nest on cell towers
In addition to raptors, corvids, and swallows, other bird species that may nest on cell towers include:
- Pigeons
- Doves
- Starlings
- House Sparrows
- Grackles
- Blackbirds
- Cormorants
- Great Blue Herons
- Rock Pigeons
- Mourning Doves
- European Starlings
- House Sparrows
These species often build nests on platforms, beams, or other supporting structures. Some are cavity nesters and may occupy crevices in towers or nest boxes installed for raptors if present.
Why birds nest on cell towers
There are several key reasons why a diversity of bird species are attracted to nesting on cell towers:
- Height above ground provides protection from many predators
- Tower structures offer nest anchoring points and surfaces
- Towers are elevated above vegetation giving better access to airspace for hunting and foraging
- Isolated location reduces competition for nest sites with other birds
- Linear arrangements of towers along migration routes provides network of nesting sites
- Tower lights attract night-migrating birds providing food source
- Towers provide nesting sites in landscapes lacking natural nest substrate
The combination of factors unique to cell towers makes them attractive and adaptable nesting sites for a wide array of bird species with different nesting requirements.
Issues caused by bird nests on cell towers
While cell towers provide benefit to birds as nesting habitat, the presence of nests can also create issues for tower function and maintenance. Some problems associated with bird nesting on cell towers include:
- Nest materials can damage antennas and other sensitive equipment
- Bird droppings can corrode and degrade equipment over time
- Nests can block airflow or vents causing equipment overheating
- Adult birds and chicks can peck or chewing on wires or cabling
- Nests can become fire hazards from accumulation of combustible materials
- Nesting birds deter maintenance workers from accessing equipment
- Towers may need to be temporarily shut down during nesting season to avoid disturbing protected birds
These issues can lead to disruptions or degradation of communication signals, increased operation and repair costs, and regulatory problems. Proper monitoring and management of bird nests is important for reducing impacts to networks.
Preventing birds from nesting on cell towers
Various exclusion methods can be used to try to prevent birds from building nests on cell towers. Common approaches include:
- Blocking access to potential nesting sites with mesh, spikes, or slope modifications
- Installing deterrent devices such as moveable predator effigies, reflective tape, or noise emitters
- Stringing wire, cables, or other materials across nesting surfaces
- Applying chemical bird repellents or surface gels to make sites less attractive
- Using falconry or trained raptors to patrol and harass birds away from towers
The effectiveness of nest prevention methods can vary greatly depending on the bird species, tower design, and persistence of application. Often a combination of multiple techniques is needed over the long term.
Managing active bird nests on cell towers
Once birds have constructed active nests on a cell tower, they are protected under federal law and cannot be disturbed or removed until young have fledged. Recommended practices for managing active nests include:
- Conducting nesting surveys before any tower maintenance work
- Marking and mapping location of all active nests
- Establishing no-activity buffer zones around active nests
- Avoiding all non-emergency maintenance work within nesting zones until young have left
- Scheduling any necessary equipment retrofitting or upgrades outside breeding and nesting seasons
- Using deterrents to prevent re-nesting after young have fledged
Careful planning of maintenance activities and diligent monitoring is key to allowing normal network functioning while ensuring nests remain undisturbed as required by law.
Regulations related to birds nesting on cell towers
There are federal and state laws protecting most native bird species in the United States. Regulations related to cell towers and nesting birds include:
- Migratory Bird Treaty Act – prohibits harming or destroying active nests for all covered species
- Bald and Golden Eagle Protection Act – prohibits disturbing bald eagle and golden eagle nests
- Endangered Species Act – protects nests of federally threatened and endangered bird species
- State wildlife regulations – may protect certain state-listed species nests
Violating regulations by harming birds or active nests can result in fines, work stoppages, and revocation of operating permits. Following proper procedures for identifying and protecting nests is essential for legal compliance.
Bird Species | Typical Nest Locations on Towers | Nesting Materials |
---|---|---|
Red-tailed Hawk | Top platforms | Large sticks |
American Crow | Horizontal beams below raptor nests | Sticks lined with bark, paper, plastic |
Cliff Swallow | Vertical surfaces under overhangs | Mud pellets |
Mourning Dove | Platforms, beam cruxes | Small sticks |
Barn Swallow | Horizontal surfaces under overhangs | Mud cup nests |
Eastern Phoebe | Concrete pads near base | Moss lined with mud, grass |
This table provides examples of where different bird species tend to build nests on cell towers and what materials they use in nest construction.
Conclusion
Cell towers represent important nesting habitat for a wide array of bird species. Raptors, corvids, swallows, and songbirds all build nests on towers to take advantage of the elevation, protection, and nesting surfaces they provide. However, nests can also create operating problems for tower infrastructure. Understanding what species nest on towers and employing proper monitoring, management, and exclusion techniques are key to allowing vital communication networks to coexist with wild bird populations.