Why one broken cue isn't the whole story
Most animals navigate with more than one sense. A nocturnal migrant may read the sky's light and darkness, polarized light patterns, landmarks, and sound, and it weighs these against each other. That layering is what makes navigation robust: if one cue is weak, another can carry the animal through. The trouble with human-made pollution is that it tends to hit several of these channels at once, so the backup systems fail together rather than one at a time.
A review of sensory pollution makes this point directly: sound and light pollution co-occur in altered habitats, and their combined effect on perception and performance is not simply the sum of two separate problems [3]. The same review notes that artificial light has not been clearly linked to impaired detection of visual signals, but it may interfere with the use of spatial cues during navigation [3]. In other words, the light may not blind the animal; it may mislead it about where it is.
Light can hijack the compass rather than just dim the view
For nocturnal animals, light is both a signal and a map. A review of nocturnal animals describes light pollution as scrambling polarized light navigation, which can throw off orientation for species that read the sky's polarization pattern [5]. This is a different kind of harm from glare or reduced visibility: the animal's directional reference itself becomes unreliable.
Migratory birds offer a concrete case. In a study of nocturnal migrants moving through urbanized landscapes, the birds appeared to use light or darkness, rather than land cover, as navigational cues, and artificial light at night combined with built structures was associated with reduced functional connectivity of the aerial habitat they move through [1]. Functional connectivity here means how easily animals can actually move between usable areas; the finding is that the night sky's human-made glow and the built environment together change which routes remain practical [1]. The study supports a link between light and altered movement, though it does not directly test how the birds combine light with other cues [1].
Noise adds a second layer of interference
Noise pollution is often treated as an acoustic problem, but it can also compete with the spatial information an animal uses to orient. The sensory-pollution review frames noise and light as co-occurring stressors whose interaction shapes behavior, which is why studying them one at a time can understate the effect [3]. A discussion of marine species makes a similar point: animals such as birds and sea turtles rely on natural cues, and human-made noise and light can disrupt those cues [2].
Bats show how the layers stack. A review of bat responses to wind-energy development examines sensory pollution from light and noise across multiple senses, and notes that some human-made signals can resemble cues bats follow during migration or commutes to high-quality habitat [4]. That resemblance is the dangerous part: a false cue doesn't just add noise, it can pull an animal toward a place or path it would not otherwise choose [4]. The review treats this as a possibility raised by the sensory evidence, not a demonstrated cause of bat deaths at turbines [4].
Habitat change decides how much a wrong cue costs
The same misleading cue matters more when the landscape offers fewer alternatives. When habitat is fragmented, an animal that follows a bad cue has less room to correct and fewer intact patches to redirect toward. The nocturnal-animals review groups habitat fragmentation with light and noise pollution as interacting human pressures on navigation and timing [5], and the migratory-bird study ties built structures and artificial light to reduced connectivity of the aerial habitat [1].
This is where the layered-cue idea becomes practical. A single pollutant might be survivable if other cues and other habitats remain available; the concern is the combination of a corrupted cue and a shrunken landscape. The evidence supports that combination as a plausible mechanism for disrupted navigation [1][3][5], but the studies reviewed here generally examine pollutants and habitat separately or in pairs rather than measuring how animals actually reweight one cue against another when several are altered [1][3]. That gap is the honest edge of what these findings can tell us.
Sources used in this answer
Urbanization and artificial light at night reduce the functional connectivity of migratory aerial habitat
Urbanization and artificial light at night were associated with reduced functional connectivity of migratory aerial habitat, and nocturnal migrants appeared to use light or darkness rather than land cover as navigational cues.
The sensory ocean: exploring noise and light pollution as blue crime
The paper examines how noise and light pollution disrupt natural navigational cues in marine species such as birds and sea turtles.
Pollution going multimodal: the complex impact of the human-altered sensory environment on animal perception and performance
Co-occurring sound and light pollution interact across sensory modalities, and artificial light may interfere with the use of spatial cues during navigation even without impairing visual signal detection.
A multisensory approach to understanding bat responses to wind energy developments
Human-made light and noise at wind-energy developments can resemble cues bats follow during migration or commutes to high-quality habitat, viewed through a multisensory lens.
Nocturnal Animals-Adapted or Inherited Plasticity: Adapted or Inherited Plasticity
Light pollution scrambles polarized light navigation in nocturnal animals, and light, noise, and habitat fragmentation act as interacting human-induced pressures.