Sight is arguably the most important of a bird’s senses, with it being vital for finding food, avoiding predators, flying safely, and seeking a mate.
We know that some birds are nocturnal and are highly active at night, and can infer that they must have some degree of vision in the dark, but is that the case for all birds? Can all birds see at night, or is their eyesight limited when darkness falls? Read on to learn more.
Nocturnal birds have a highly developed sense of night vision, enabling them to fly, hunt, mate, and raise young in darkness. Most bird species are adapted for better vision during daylight hours, with only limited eyesight once night falls.
Although some songbirds may be occasionally heard singing at night, they are unlikely to be seen in flight unless they have been disturbed from their nesting site or overnight roosting spot. Darkness severely impairs their ability to navigate safely, and light is needed for foraging successfully and finding a suitable mate.
Nocturnal birds’ eyes are specially adapted to function effectively in the lowest light conditions, and are anatomically different to those of diurnal birds. To find out just what enables owls, nighthawks, and woodcocks to see in the dark, please keep reading.
Tawny Owl perched in a tree at night
Nocturnal birds, such as night herons, owls, frogmouths, and nighthawks, are active at night, hunting, foraging for food, navigating the skies, and caring for their young in the dark. To understand how their vision differs from that of diurnal birds, let’s take a look at the anatomy of a nocturnal bird’s eye.
The eyes of nocturnal bird species are tubular in shape. They contain fewer cones (color detecting cells) compared to the eyes of birds that are active in daylight. In contrast, they have a higher density of rod cells that help with night vision, as they function well in dim light. Nocturnal birds’ eyes possess pathways through which rods link up to the same “dark” circuits used by cones. This allows them to see movement, edges, and silhouettes in dim light.
Close up of a Yellow-crowned Night Heron
Most birds that are active during the day have very poor vision once night falls. Nocturnal birds are in the minority, and have adapted eyesight that allows them to carry out all of their activity in the dark.
Total darkness impedes the vision of all birds. For example, oilbirds living in pitch-black caves rely on echolocation to navigate in the absence of any light sources.
Some small birds are occasionally active at night, and you may hear songbirds such as thrushes, robins, sparrows, and warblers singing after dark. These birds often sing at night to attract a mate or establish a territory, but are not classed as nocturnal, and their night vision is not refined.
Both American and European Robins are commonly heard singing at night
Birds that are active in daylight do not fly after dark as their vision is limited, which makes navigation more challenging and puts them at risk of predation. Birds need a period of restful sleep each night to restore and conserve their energy levels.
Some birds that are normally active during the day actually undertake their annual migration flights under cover of darkness, including orioles, thrushes, flycatchers, warblers, and sparrows, Night migrations enable them to avoid many predators.
Some birds are active at night, and it is totally normal for them to be spotted in flight or hunting. In urban areas where there is a lot of artificial light from homes, buildings and traffic, birds may continue to be active after dark to some extent and may also be spotted roosting in trees.
Apart from nocturnal birds, it is unusual to see birds that are normally active during the day at night, unless they have been disturbed or had their nest or roosting spot disturbed by a predator.
Birding at night can be a fascinating experience, but may bring challenges as your eyes need time to adjust to the light. You are more likely to be able to identify birds at night from listening to their calls, but may be lucky enough to get a glimpse of an owl out hunting.
Nighthawks are active at both dawn and dusk
Unusual light at night can affect a bird’s natural behavior patterns, and research continues into whether artificial light disrupts the natural physiology of birds. Nocturnal birds are adapted for functioning better in the dark, while diurnal birds do need darkness in order to get sufficient sleep.
Seeing color is less necessary for nocturnal birds than for birds active in daylight, who rely on their ability to distinguish colors to find mates, escape predators, and forage for food. Nocturnal birds’ eyes have more rod cells than cones, which means that they are better developed for seeing in low light than for identifying different colors.
The outline of a Night Heron with one of their chicks
Crows do not see particularly well at night, so are not usually active after dark. Crows are not nocturnal; at night, they are most likely found roosting together in communal roosts, in the highest branches of trees. However, in built-up areas with lots of artificial light, it may be more common to see crows after nightfall.
Pigeons are known for their keen eyesight. However, although they have highly sensitive vision during the day, at night it is not quite so accurate. They are able to use the moon and street lamps to navigate once night falls, but you will generally not see a pigeon active in the dark unless it has been startled or scared from its roosting spot.
A bird perched in a tree at night
It’s not unusual to hear a robin singing at night, especially in areas where there are lots of street lamps. Both City-dwelling American and European robins tend to have unusual sleep patterns, but their eyesight is not particularly strong after dark and they are unlikely to be seen feeding or foraging until after the sun has risen.
Doves’ eyesight at night is poor; they spend nights roosting, and will not fly in darkness unless disturbed.
Cockatoos cannot see well in the dark, with their night vision being comparable to that of humans.
Budgies have very poor night vision and cannot see at all well in the dark. As budgies require around 12 hours of sleep per night, it’s recommended to cover their cage at night so that they are in total darkness as this allows them to get the rest they need.
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