Birds frequently collide with windows, a common issue for homeowners and bird enthusiasts. These incidents often result in injury or fatality for birds, posing a significant challenge. Understanding the reasons behind these collisions is a crucial step toward mitigating their impact on avian populations.
The Illusion of Open Space and Habitat
A primary reason birds fly into windows stems from their inability to perceive glass as a solid barrier. This occurs due to transparency and reflection. Birds may see through a clear window to vegetation or open space, mistakenly believing it is a clear path. This “tunnel effect” is particularly misleading when windows are positioned opposite each other, creating a seemingly open corridor.
Windows often reflect the surrounding environment, such as the sky or trees. Birds interpret these reflections as extensions of their natural habitat, attempting to fly into what appears to be an unobstructed landscape. This confusion can lead to high-speed impacts as birds navigate instinctively towards what they perceive as safe territory.
Additional Factors Increasing Risk
Other circumstances also contribute to bird-window collisions. Territorial aggression can lead birds to strike windows when they perceive their reflection as a rival. This behavior is prevalent during breeding seasons as birds defend their territory. While often less fatal than a direct flight collision, it can still cause distress and minor injuries.
Nocturnal migration presents a heightened risk, especially for songbirds. Artificial lights from buildings can disorient migrating birds, drawing them off course into urban areas. Low visibility conditions, such as fog, exacerbate this disorientation, increasing collision likelihood. Attractants like bird feeders or dense landscaping near windows can draw birds closer to glass, increasing collision risk.
Making Windows Bird-Safe
Several strategies can make windows more visible to birds, reducing collisions. Applying patterned films, decals, or tapes to the exterior breaks up reflections and transparency. Patterns should be spaced no more than two inches apart horizontally and vertically to prevent birds from flying through perceived gaps. UV-visible products, which birds can see but humans cannot, offer a less intrusive aesthetic solution while providing visual cues.
External screens, netting, or vertical cords hung four inches apart in front of windows can create a physical and visual barrier. Painting patterns with tempera paint or using a dry bar of soap are other accessible options. The goal is to transform the window into a clearly perceptible obstacle, prompting birds to alter their flight path safely.
Assisting a Stunned Bird
If a bird strikes a window and appears stunned, a calm approach is advisable. Gently place the bird into a small paper bag or a cardboard box lined with a soft cloth. Move the container to a dark, quiet, warm location away from pets. This environment helps reduce stress and allows the bird to recover.
Do not provide food or water, as the bird may have internal injuries. Monitor the bird for one to two hours; if it recovers and can fly strongly, release it outdoors in a safe area away from the window. If the bird remains stunned, appears injured, or does not recover, contact a local wildlife rehabilitator for guidance.