Nocturnal Birds of Prey - Characteristics and Examples
Nocturnal birds of prey are largely considered to be those that belong to the order Strigiformes. Commonly known as owls, this order is further broken into the families Strigidae and Tytonidae. These are known as ‘true owls’ and ‘barn owls’, respectively. These are compared with diurnal birds of prey, a group which contains various raptors including falcons, eagles and hawks. Both are adapted in certain ways to enable them to be active at different times of the day. While it is generally true that owls have nocturnal habits while other raptors are more active during the daytime, there are various exceptions to these broad rules.
At AnimalWised, we take a closer look at nocturnal birds of prey. We discover the characteristics of nocturnal raptors, as well as some examples of species indicative of their type.
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Characteristics of nocturnal birds of prey
Nocturnal raptors are birds of prey, meaning they are carnivorous and predatory. Generally speaking, there are fewer bird species with nocturnal habits than diurnal birds. This also applies to raptors, with there being less nocturnal birds of prey than diurnal species. Although not exclusively, most nocturnal birds are carnivores. These nocturnal predators use the darkness for stealth when hunting.
All raptors have certain adaptations which make them such good hunters. These include the ability to fly fast, very strong talons and razor-sharp beaks. Nocturnal birds of prey have additional adaptations which allow them to hunt better at night[1]. These include large eyes which make them capable of seeing in low-light conditions.
Their ears are similarly adapted to nighttime behaviors. They are at a different height and orientation compared to diurnal birds of prey which allows them to pick up sound when vision is more difficult. Nocturnal raptors can also turn their head almost 270 degrees, providing a larger range within their environment.
During the day, nocturnal birds of prey tend to sleep in tree hollows or crevices they can find. During breeding season, these areas are used to nest and lay eggs. Due to their heightened night vision, the daytime sun can be damaging to their eyes. Their plumage is also adapted to the nighttime. This is due to their cryptic plumage, allowing them to go almost unnoticed through the branches of trees at night.
Such plumage adds to their stealth ability. It is not only the look of the plumage, but the shape and structure which gives them the advantage. Owls have tiny serrations on their remiges (flight feathers of the wings) which allows them to fly silently. This gives them the advantage over prey animals which have similarly good hearing. They often do not hear the owl's approach until it is too late. It is also hypothesized that this noise reduction also benefits the owl themselves since they can better hear their environment[2].
The inner edge of the remiges has a silky fringe that reduces turbulence. The surface of these feathers has a very smooth appearance, due to the presence of structures called barbicelos.
Types of nocturnal birds of prey
As stated in the introduction, most nocturnal raptors are from the order Strigiformes. This means they are mainly types of owls. Within the two families of true owls (Strigidae) and barn owls (Tytonidae), we can find many genera. These carnivorous birds have various differences, despite all being types of nocturnal birds of prey. We look at some of the species in these genera.
Eagle-owls or horned owls (genus Bubo)
The largest nocturnal birds of prey belong to the genus Bubo. These birds are either from the New World and known as horned owls or from the Old World and known as eagle-owls. Many weight over 2.2 lb (1 kg). As is common in raptors, females are larger than the males. This is one of the few forms of sexual dimorphism in these animals.
There are about 20 species within this genus of owls, spread all over the planet except in Antarctica. They are usually characterized by having tufts of feathers on their heads. Some species such as the snowy owl (Bubo scandiacus) have lost it. They are birds of prey, widely used in falconry, usually feed on small vertebrates and always hunt at night.
Some of the owl species in this genus are:
- Eurasian eagle-owl (Bubo bubo)
- Spotted eagle-owl (Bubo africanus)
- Greyish eagle-owl (Bubo cinerascens)
- Barred eagle-owl (Bubo sumatranus)
- Great horned owl (Bubo virginianus)
- Cape eagle-owl (Bubo capensis)
Eared owls (genus Asio)
Eared owls are from the genus Asio. They are distributed across all continents except Antarctica and Oceania. The species Asio flammeus or short-eared owl is the most widespread. They are medium-sized birds, smaller than eagle owls, but larger than other nocturnal birds of prey.
These nocturnal raptos also have tufts on their heads, but their most striking feature is that they have a disk-shaped face. Although they are considered nocturnal birds of prey, these animals are considered crepuscular, meaning they are most active at dusk and dawn.
Some species of eared owls include:
- Long-eared owl (Asio otus)
- Abyssinian owl (Asio abyssinicus)
- Madagascar owl (Asio madagascariensis)
- Marsh owl (Asio capensis)
- Short-eared owl (Asio flammeus)
- Stygian owl (Asio stygius)
Nocturnal birds of prey names
Earless owls or wood owls (genus Strix)
Owls from genus Strix are medium nocturnal birds of prey. They are characterized by facial discs, a highly rounded head, no head tufts and the presence of black eyes in most species. They are very nocturnal, specialized for hunting in almost pitch black environments. They live in forests and jungles all over the world.
Like almost all owls, they nest in natural cavities in trees, rocks, cliffs, abandoned nests of large birds and nest boxes. They can even live on the ground under bushes or trees. They are both monogamous and bigamous animals. We detail the habitats of nocturnal birds of prey more generally with our article on where do owls live?
There are more than 20 species of tawny owls, many of them divided into multiple subspecies:
- Barred owl (Strix varia)
- Ural owl (Strix uralensis)
- Mottled owl (Strix virgata)
- Tawny owl (Strix aluco)
- Fulvous owl (Strix fulvescens)
- Great gray owl (Strix nebulosa)
- African wood owl (Strix woodfordii)
Little owls (genus Athene, Glaucidium, Micrathene, Xenoglaux and Aegolius)
Little owls are part of the subfamily of true owls known as Surniinae). They are so-called because they do not usually measure more than 11" (28 cm) in length. They have a rounded body with a stocky appearance. The plumage is usually heavily mottled brown. They live in Eurasia, America and Africa, being absent in Oceania and Antarctica. They mainly mainly on insects, although they can also capture small mammals.
The little owl species are divided into five genera:
1. Genus Athene:
- Burrowing owl (Athene cunicularia)
- Spotted owlet (Athene brama)
- Little owl (Athene noctua)
2. Genus Glaucidium:
- Eurasian pygmy owl (Glaucidium passerinum)
- Andean pygmy owl (Glaucidium jardinii)
- Asian barred owlet (Glaucidium cuculoides)
- Pernambuco pygmy owl (Glaucidium mooreorum)
3. Genus Micrathene (contains a single species):
- Elf owl (Micrathene whitneyi)
4. Genus Xenoglaux (contains a single species):
- Long-whiskered owlet (Xenoglaux loweryi)
5. Genus Aegolius:
- Northern saw-whet owl (Aegolius acadicus)
- Boreal owlet (Aegolius funereus)
- Buff-fronted owl (Aegolius harrisii)
- Unspotted saw-whet owl (Aegolius ridgwayi)
Scops owls (genus Otus)
Scops owls of the genus Otus are extremely cryptic birds, disappearing completely when they are next to the bark of a tree. They have tufts on their heads and mainly feed on invertebrate animals, rarely hunting mammals.
They are small birds at around 8" (20 cm) in length and do not usually weigh more than 3.5 oz (100 g). There are some exceptions such as the giant scops owl (Otus gurneyi) which measures about 12" (30 cm). They are monogamous birds. More than 50 species of scops owls are known, distributed throughout the world, except Antarctica and Oceania.
Some of these species are:
- Eurasian scops owl (Otus scops)
- Collared scops owl (Otus lettia)
- Indian scops owl (Otus bakkamoena)
- Oriental scops owl (Otus sunia)
- White-fronted scops owl (Otus sagittatus)
- Pallid scops owl (Otus brucei)
- African scops owl (Otus senegalensis)
Barn owls (genera Tyto and Phodilus)
Barn owls belong to the genera Tyto and Phodilus, although those in the latter are also known as bay owls. They are medium-large sized birds. One of its main features is its heart-shaped facial disc. Species in the genus Tyto do not have head tufts, unlike those in the genus Phodilus which do.
They usually have white, beige or brown plumage. They are found on all continents, avoiding polar or desert areas. They feed on small vertebrates and can hunt in total darkness. The most studied species of owl is the barn owl (Tyto alba).
Other species of owls are:
- Ashy-faced owl (Tyto glaucops)
- Lesser sooty owl (Tyto multipunctata)
- Greater sooty owl (Tyto tenebricosa)
- Eastern grass owl (Tyto longimembris)
- Taliabu masked owl (Tyto nigrobrunnea)
- Oriental bay owl (Phodilus badius)
- Itombwe owl (Phodilus prigoginei)
You can learn more about the feeding habits of owls with our article on how to birds eat?
Are all owls nocturnal birds of prey?
We have already mentioned the evolutionary adaptations owls have for being active during the night. Almost all owls are nocturnal, although we already mentioned some have crepuscular habits. This doesn't mean you will never see an owl during the daytime. There are various species which may be most active at night, but which also have some diurnal habits.
It is not known whether the common ancestor of all raptors was diurnal or nocturnal. We do know that some owl species have had greater periods of diurnality during their evolution[3]. While diurnal behaviors in owls are rare, there are some species which known to have mostly diurnal habits[4]. They include:
- Northern hawk owl (Surnia ulula)
- Burrowing owl (Athene cunicularia)
- Northern pygmy owl (Glaucidium californicum)
- Short-eared owl (Asio flammeus)
Even within these species, the periods of greatest activity can also vary. Despite being known as nocturnal birds of prey, it is important to remember that individual species may differ behaviorally.
Are all nocturnal birds of prey owls?
The majority of bird species are diurnal, but there are nocturnal birds which are not owls. These include the nightingale (Luscinia megarhynchos), North Island brown kiwi (Apteryx mantelli) and the Kākāpō (Strigops habroptilus).
Despite being types of nocturnal birds, they are not birds of prey. The nightjar (also known as the nighthawk) is a nocturnal bird which eats mainly insects, but they are no considered a bird of prey.
Although we know owls sleep during the day, there is much more to their slumber. We learn about it in our article on how do owls sleep?
If you want to read similar articles to Nocturnal Birds of Prey - Characteristics and Examples, we recommend you visit our Facts about the animal kingdom category.
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https://doi.org/10.1093/gbe/evaa166
2. Clark, C. J., LePiane, K., & Liu, L. (2020). Evolutionary and Ecological Correlates of Quiet Flight in Nightbirds, Hawks, Falcons, and Owls. Integrative and comparative biology, 60(5), 1123–1134. https://doi.org/10.1093/icb/icaa039
3. Espíndola-Hernández, P., Mueller, J. C., & Kempenaers, B. (2022). Genomic signatures of the evolution of a diurnal lifestyle in Strigiformes. G3 (Bethesda, Md.), 12(8), jkac135. https://doi.org/10.1093/g3journal/jkac135
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https://doi.org/10.1073/pnas.2119217119
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BirdLife International (2016). Strix aluco. The IUCN Red List of Threatened Species 2016: e.T22725469A86871093.
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