Pigeons are a common sight in cities around the world. These birds seem quite comfortable living alongside humans, nesting on building ledges and gathering in town squares to feed. But some people wonder if all that artificial light affects pigeons. Are pigeons afraid of light? Let’s take a closer look at what science tells us.
Do pigeons prefer darkness?
Pigeons are diurnal birds, meaning they are most active during the daytime. Their eyes are adapted to seeing well in bright daylight. So pigeons do not inherently prefer darkness. However, artificial night lighting in cities has led to changes in pigeon behavior.
Studies have shown that pigeons in urban areas with more light pollution start their morning activity earlier than pigeons in darker areas. The extra artificial light appears to shift their circadian rhythms, altering when they wake up and go to sleep.
Pigeons also begin their evening roosting later in brighter cities. The abundance of artificial light encourages them to prolong their daytime routines after sunset. So while pigeons are not nocturnal, excess nighttime light does disrupt their natural cycles.
Do pigeons avoid well-lit areas?
Research suggests pigeons actually prefer well-lit areas at night. In one study, scientists recorded the roosting spots chosen by pigeons in the Italian city of Milan. They found pigeons were more likely to roost on buildings illuminated with artificial light at night.
The light appeared to give them visibility and make them feel less vulnerable to predators. The pigeons avoided darker, shadowed areas at night. Other studies have similarly noted flocking pigeons’ attraction to artificial light sources.
So rather than avoiding brightly lit city areas, pigeons seem to actively congregate in well-lit spots after dark. Additional night lighting may make them feel safer.
Does light alter predator interactions?
Abundant artificial light at night does change the balance of power between pigeons and their predators in cities. Many predatory birds that hunt pigeons rely on daylight to see.
Extra illumination at night gives pigeons an advantage. It allows them to spot approaching predators more easily. However, some predators like peregrine falcons have adjusted by using urban light to their benefit, improving their success hunting pigeons at night.
Night lighting also impacts pigeons’ interactions with less avian predators. Rats and mice often prey on pigeon eggs and hatchlings. Brighter conditions at night may make pigeons more vulnerable in their nests.
Illumination likely influences complex urban predator-prey dynamics between pigeons and other species. More research is needed to clarify these relationships.
Do sudden lights startle pigeons?
While pigeons do not seem averse to artificial light itself, sudden bright lights can startle them. Pigeons have a strong fight-or-flight response. Surprising illuminations at night likely cause panic, making them abruptly scatter from their roosts.
People sometimes purposefully use flashing lights to deter unwelcome flocks of pigeons gathering in locations late at night. The unexpected lights appear to temporarily disturb and displace them. So pigeons may not fear light in general, but abrupt illumination changes understandably distress them.
Do lasers harm pigeons?
Powerful lasers that are becoming more commonplace in cities risk permanently damaging pigeons’ vision. Pigeons’ eyes are anatomically similar to human eyes. Exposure to concentrated beams from handheld lasers can burn their retinas, leaving permanent scars.
This causes substantial vision impairment and even blindness. In one study, lasers caused irreparable ocular damage in trois pigeons researchers examined. This severe harm to pigeons’ eyes highlights the need for responsible and ethical laser use around wildlife.
Conclusion
Pigeons evolved as a diurnal species and naturally prefer daylight conditions. While artificial night lighting shifts their activity patterns, it does not appear to scare off urban pigeon flocks. In fact, well-lit city areas seem to attract congregating pigeons after dark, potentially offering protection against predators.
Sudden bright lights can startle pigeons at night but regular illumination does not make them avoid urban spaces. However, extremely bright lasers can severely hurt pigeons’ eyesight. When it comes to pigeons and light, permanent vision damage from lasers remains the biggest concern in cities today.
Pigeons’ Natural History
To better understand how artificial lighting affects pigeons, it helps to consider their evolutionary history and vision adaptations. Here is some background on these urban birds:
Pigeons are descended from wild rock doves
The pigeons found living alongside people in cities around the globe descended from wild rock doves. Rock doves naturally inhabit sea cliffs and canyons across Europe, Africa, and Asia.
Originally cliff-dwellers, these doves began nesting on human structures and were gradually domesticated over thousands of years. Later, escaped domestic pigeons returned to living wild in proximity to people.
The pigeons now thriving in urban areas derive from these formerly domesticated rock doves. Their urban-dwelling descendants are sometimes called fancy or street pigeons.
Pigeons are highly adaptable birds
Rock doves prove highly adaptable to new and changing environments. This has enabled their feral pigeon descendants to successfully colonize cities across the globe.
Pigeons exhibit an impressive ability to adjust their behavior and rhythms to suit local conditions. For example, urban pigeons have learned to navigate subway systems, cross busy roads, and find food among skyscrapers.
The adaptability of pigeons allows them to alter their activity patterns to accommodate artificial lighting. Their flexible behavior helps them thrive among the bright lights of cities at night.
Pigeons have excellent vision suited to daylight
Pigeons have sophisticated visual systems well-adapted for daytime activity. They have large eyes relative to their body size and compact yet powerful visual processing centers in their brains.
Pigeons have excellent visual acuity. Their color vision and ability to see ultraviolet light also surpasses that of humans. Pigeons can perceive light flickering up to 145 times per second, much faster than the human eye.
Unlike owls, pigeons lack many adaptations for nocturnal vision. But their sophisticated daytime vision allows urban pigeons to adeptly navigate the complex environments of well-lit cities.
Flocks increase pigeons’ nighttime safety
Pigeons strongly prefer to gather in flocks, especially at night. Flocking behavior provides safety in numbers. Being part of a group helps pigeons spot potential predators and collectively take evasive action.
This instinct likely explains why pigeons appear to congregate in well-lit urban areas after dark. Large flocks give them the greatest protection against nocturnal predators like rats. The illumination further aids their vision to see threats.
So flocking draws pigeons to light but it is predator protection, not the light itself, that they really seek at night. Artificial lighting simply allows them to form bigger, safer flocks.
Effects of Artificial Lighting on Pigeons
While pigeons are highly adaptable, urban night lighting does impact pigeon physiology and behavior. Here are some of the effects research demonstrates:
Disrupted circadian rhythms
Abundant artificial light at night disturbs pigeons’ natural circadian cycles. In low light, pigeons secrete melatonin which makes them sleepy. Extra illumination suppresses melatonin and pushes back feelings of sleepiness.
Urban light pollution alters pigeons’ circadian clock, causing them to start mornings earlier and delay roosting at night. Disrupted circadian rhythms likely contribute to pigeons becoming active before dawn and after dusk in cities.
Reproductive changes
Research on other bird species indicates light pollution can reduce reproductive hormone levels, sperm quality, and fertility. While not yet studied in pigeons specifically, artificial light at night likely influences their reproductive physiology too.
Altered circadian rhythms may also change the timing of pigeon reproduction. This can cause issues if timing gets misaligned with ideal seasonal conditions for breeding.
Orientation and navigation difficulties
Wild pigeons use a combination of visual landmarks, solar cues, and the earth’s magnetic field to orient themselves and navigate during flight. But artificial light pollution makes it harder for pigeons to see stars and disrupts their magnetic compass sense.
Bright urban lighting also obscures natural visual cues. It can cause pigeons to become confused and lost, especially young birds on their first flights. However, over time city pigeons learn to rely more on urban landmarks and less on disrupted celestial guides.
Attraction to light traps
While additional city lighting draws in flocks, extremely bright nocturnal light sources can become disorienting traps for pigeons. Brightly lit skyscrapers and illuminated monuments attract circling flocks.
Birds may become stuck flying loops around these buildings, unable to find a landing spot. Exhausted pigeons can eventually fall to the ground. Light pollution can also draw pigeons off course during migration.
Greater threat from light-aided predators
As mentioned earlier, some pigeon predators take advantage of night lighting to more successfully hunt. Peregrine falcons in cities have learned to improve their success snatching pigeons under artificial illumination.
And bright light aids predators like rats and mice that threaten pigeons in their nests after dark. So excess artificial light has both advantages and disadvantages when it comes to threats.
Increased collision risks
Low-level urban lighting appears to increase risks of pigeons colliding with buildings and other structures. Disorienting light conditions make it harder for pigeons to see and avoid obstacles in their path.
Pigeons flying through brightly lit areas at night are at greater risk of fatally crashing into buildings. Structural collision is already a substantial cause of pigeon mortality in cities. More artificial light exacerbates this.
Improved visibility of litter
On the beneficial side, extra illumination helps pigeons spot potential food sources at night. Litter and refuse that pigeons feed on is easier for them to identify under street lights and other artificial sources.
So supplemental urban lighting enables pigeons to more successfully scavenge for discarded edible waste overnight, increasing their access to food.
Effects of Different Lighting Conditions
Not all artificial lights impact pigeons equally. Here is a look at how different lighting conditions affect pigeons in cities:
Chronic bright illumination versus darkness
As a diurnal species, pigeons naturally prefer daylight conditions. But completely dark areas at night leave pigeons feeling exposed and vulnerable.
So paradoxically, brightly lit areas provide greater perceived safety for flocking pigeons after sunset. Chronic bright illumination lets them see predators and gather in secure large groups.
Cool white lighting versus warm lighting
Different colored lighting appears to have varying effects on pigeons. Their vision is shifted towards cool blue and green wavelengths, so pigeons likely see warm artificial lighting as relatively darker.
Cool white light provides greater visibility for pigeons at night. But more research is needed comparing how their behavior differs under warm versus cool illumination.
Continuous lighting versus intermittent flashes
While pigeons do not inherently fear darkness, sudden intermittent flashes of light startle them at night. Continual stable illumination allows them to adjust, while erratic strobing lights disturb their behavior.
Intermittent pulses of extremely bright light are used specifically to deter pigeons from gathering in locations overnight. Darkness with abrupt flashes frightens them more than constant dim lighting.
Point-source lighting versus diffuse illumination
Brilliant point-source lights at night like spotlights or lasers can dazzle, disorient, and damage pigeons’ vision. Broad, diffuse urban illumination allows them to see their surroundings more naturally.
Diffuse street lighting supports flocking and navigation better than blindingly bright point-source lights. Glare from intense narrow beams impairs pigeons’ visual abilities and hinders their movement.
Elevated lighting versus ground-level lighting
Elevated lighting on poles and high buildings benefits pigeons more than ground-level illumination. High lighting allows them to survey and navigate across a landscape.
Low ground-level lights often just create glare and blurry shadows. Elevated street lights let pigeons spot potential perches and food. So for pigeon vision, high-angled lighting works better than light spread across the ground.
Best Practices for City Lighting Around Pigeons
Here are some recommendations to minimize potential issues from artificial lighting for urban pigeons:
Use lower-intensity illumination
Brighter light attracts more pigeons but also increases risks of disorientation and collisions. Lower-level lighting reduces glare and allows pigeons to see obstacles and navigation features.
Limit illumination levels to the minimum needed for human visibility and safety. Direct lights only where light is required. Use motion-activated and dimmable fixtures to avoid over-illumination.
Minimize blue light emission
Pigeons see light in the blue and green spectrum most clearly. Minimizing blue wavelengths in outdoor lighting reduces attraction for pigeons while still aiding human color vision.
Choose warmer color temperature lighting (2700-3000K). Filter out blue wavelengths using coatings or lens diffusers when possible. This limits disruption of pigeon vision and circadian cycles.
Reduce intermittent flashes
While intermittent bright flashing can disperse pigeon flocks, it distresses the birds. Use continuous illumination rather than irregular strobing or flashing whenever possible.
For necessary intermittent lights, use longer cycles between pulses to minimize disturbance. Give pigeons a chance to settle between disruptions.
Avoid sudden lighting changes
Gradual lighting transitions help pigeons adjust their behavior and vision. Dim slowly at dawn and increase illumination slowly at dusk.
Program theatrical or decorative lighting sequences to gradually ramp up and down. Avoid abrupt shutoffs or illuminating dark buildings unexpectedly at night.
Light higher locations, not lower surfaces
Illuminating elevated structures and tall poles benefits pigeon navigation and vision more than ground-level flood lighting. Direct spotlights and task lighting upwards not downwards.
Avoid creating low glare and shadows across surfaces. Focus outdoor lighting on higher building facades and architectural features to highlight them.
Add pigeon deterrents in problem areas
Use netting, spikes, sloped ledges, and other passive deterrents to discourage pigeon roosting in unavoidably illuminated locations. Avoid lasers and high-intensity strobe lights which can injure pigeons.
Strategically place roost-preventing surfaces near spotlights, signs, and LED displays to dissuade gathering flocks attracted to the bright lights.
Balancing Pigeon Welfare and Urban Light Needs
Urban planners and wildlife advocates must seek compromise solutions to balance community lighting needs with minimizing harm to pigeons and other animals. Here are some ways to achieve shared site lighting goals:
Involve stakeholders collaboratively
Get input upfront from all parties including city officials, architects, wildlife specialists, neighborhood groups, and environmental advocates. Address needs together through an open public process instead of opposing parties reacting separately.
Adjust operating hours
Use motion sensors, timers, and dimmers to turn lights off in low human-use times like overnight and early mornings. Part-night lighting offers a compromise between safety, utility, and unintended wildlife impacts.
Improve efficiency
Use efficient LEDs to get the same or better lighting at lower wattages. New technologies like adaptive optics and tunable color allow fine control over illumination. Upgrade old fixtures to reduce energy waste and overlighting.
Follow dark sky principles
Direct outdoor lighting downward and shield bulbs to minimize sky glow. Choose full cut-off fixtures that focus illumination below the horizon. Follow International Dark-Sky Association guidelines.
Zone lighting levels
Brightly illuminate only critical areas like building entrances. Use lower lighting levels elsewhere such as in parking lots or decorative lighting. Set zoning regulations limiting commercial lighting based on proximity to habitats.
Review regularly
Assess the effectiveness of lighting plans post-installation and adjust levels based on real-world conditions. Continuously look for places to improve by reducing excess or badly directed lighting. Be ready to responsively update based on emerging technologies and wildlife research.
Conclusion
Pigeons are highly adaptable birds equipped to see well in daylight conditions. They naturally prefer to roost and nest on elevated structures. While artificial night lighting shifts pigeon behavior, it does not scare them away from urban areas.
In fact, well-lit locations often attract flocking pigeons after dark by aiding their vision and security. However, excessive or poorly designed illumination risks disorienting pigeons and enabling certain predators more successfully. Careful lighting strategies can support pigeon welfare and city needs through collaboration, efficiency, and applying the latest technology and wildlife research. With smart planning, cities can be made scintillating yet still sustainable for both people and pigeons.
