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When we think about owls we immediately think of the wise, wide-eyed, hooting bird that lurks at night. This isn't entirely wrong, in fact in many cases this is an accurate description but it is misleading to believe that owls only live their lives as soon as the sun goes down. The term ‘night owl’ was coined by the general behaviour of owls but there are actually many examples and situations that lead an owl to become active during the daytime. So if you have ever wondered 'are all owls nocturnal' or ‘are owls ever awake during the day?’ then you have come to the right place. In this article I will be exploring the sleep pattens of many owls and the different reasons you might just see an owl during the day. So are all owls nocturnal? The short answer is no, they are not. Most owls tend to favour the darkness, but not all. Sleep Patterns: In general, most owl species are nocturnal which means they sleep during the day but this isn’t always the case. There are three different sleep patterns, those that are strictly nocturnal, those that are diurnal and those that are crepuscular. Diurnal - Active during the day, sleep at night. Crepuscular - Sleep during the day, become active at dusk and dawn. Nocturnal - Sleep during the day, active during the night. It may seem, since we have these very official categories for owls sleep patterns named, that we are able to split owls into these categories quite easily but these are mostly based on generalisations. Owls are quite adaptable to the changing patterns of their preys behaviour and the weather and therefore if this means they will be more successful hunting during the day, then in the day they shall hunt! A prime example of this would be Barn Owls. Generally known as a night owl, these owls do get spotted during the day fairly often. Barn owls can switch up their routine whenever they want and have been known to switch between diurnal and crepuscular. This kind of behaviour has been linked to a few different explanations: There is less competition at different times of the day. If an owl realises they will be more successful hunting at a time where there are less predators around they may alternate to this hour.Depending on how the weather has been or how it is. Iain Taylor (1994) found that Barn Owls in south-west Scotland hunted by day usually when there had been heavy rainfall the night before. Dependant on region. Taylor also found that owls (Specifically Barn Owls) in northern Europe tend to be diurnal and those in southern Europe and the tropics tended to be crepuscular.They may focus their hunting time around their favourite prey. Barn Owls have been known to align their activity patterns with the activity of their most popular prey - the Field Vole and the Common Shrew. Nocturnal Barred Owl with distinct black eyes. I have put together a general rule table which will summarise when you are most likely to see each owl active. I have combined crepuscular and nocturnal together as these descriptions often cover the same species and any owls that live by this pattern are more unusual to see. A little tip for figuring out whether an owl is diurnal, crepuscular or nocturnal is to look at the eyes. Entirely black eyes mean nocturnal, yellow eyes mean diurnal and orange eyes mean crepuscular. Just keep in mind that sometimes these owls can decide to switch up their usual routine if needed, if something approaches a nocturnal owl during the day they will still be alert and wiling to fly to a new place to rest. Therefore nocturnal does not mean entirely inactive. See Below - Table summarising which category owl species fall into: Diurnal - Active during the dayCrepuscular & Nocturnal -Active at Dawn, Dusk and during the nightA bit of bothNorthern Hawk OwlGreat Horned OwlSnowy OwlNorthern Pygmy OwlBarred OwlLittle OwlBarn Owl (mostly)Burrowing OwlTawny OwlShort-Eared OwlLong-Eared OwlBlakiston’s Fish OwlGreat Grey OwlSpotted OwlEurasian Eagle-OwlVerreaux's Eagle-OwlNorthern Saw-Whet OwlBrown (Buffy) Fish OwlBoreal OwlFerruginous Pygmy OwlElf OwlBarking OwlSpectacled OwlTamaulipas Pygmy OwlFlammulated OwlWestern Screech OwlStriped OwlSpotted Wood OwlOriental Bay OwlWhiskered Screech OwlIndian Eagle-OwlAustralian Masked OwlLong-Tufted Screech OwlEurasian Scops OwlPowerful OwlStygian OwlNorthern White-FacedCrested OwlCollared Scops OwlSpotted Eagle-OwlBlack-banded owlBrown Wood OwlGreater Sooty OwlMiddle American Screech OwlDifferent owl species sleeping/activity habits. As you can see, the majority of owls are active during the night and this is because owls have excellent vision and hearing for hunting in the dark. All an owl must do is hear the slightest sound of their prey in both ears to know which direction it is moving in. This is because one ear receives the sound of the movement a second before the other which allows the owls to calculate the exact distance away from the prey they are. The night time often brings out more prey for owls. Rodents feel they can move around more during the night without being spotted as everything seems quieter and safer - the perfect time for the owl to strike with their silent movements with less competition. Not many birds can move quite as silently as the owl, so they are the perfect night predator. Many people assume that owls cant see very well during the day or that the sun hurts their famously large eyes but owls eyes can actually function fine during the day, just a bit differently to our eyes. The human pupil adjusts in size to control how much light it allows to hit the lens. The lens allows light through to the vitreous humor, which is a clear gel-like substance that supports the retina. Therefore a human pupil can get really small or really large (know as dilation) to let in more or less light. The smaller the pupil, the less light is let in to the lens. whereas with owls, their pupils don't get as small as ours do so they will often close their eyes half-way to account for this. This can create the illusion that the owl is asleep when it may actually be awake and alert. The Fovea is the part of the eye where the vision cells are and due to their location in an owls eyes (upper part of the retina) this enables them to see below them extremely well. This is needed for when they are flying while hunting prey on the ground. Therefore if the owl must close its eyes half way during the day, this does not affect their ability to hunt. So lets have a quick look at a few of our major night owls since we would be here all day if we went through them all! The Long-Eared owl can often be heard coming to life at night as it has a long, low hoot that can sound menacing in the dark. Long-Eared Owls are much more secretive and are usually only spotted during migration periods since they are incredibly camouflaged to their surroundings and probably the most nocturnal of all the owls. The Great Horned Owl is also known to mostly move at night and is also known for its call, it is more often heard rather than seen. Whereas while these night owls are getting their beauty sleep, owls such as the Northern Hawk Owl and the Northern Pygmy Owl are awake and hunting in the daylight. These two owls are the only two religiously known for their diurnal antics. Northern Hawk Owls are known to hunt using mainly their eyes because their hearing isn't as good as most owl species. This is not to say their hearing is bad, it is still pretty impressive as these owls can hear prey beneath snow! Their reliance on their eyesight more than their hearing though shows why these owls prefer to hunt during the day when they can see everything even better. The Northern Pygmy Owl similarly has greater reliance on its eyesight over its hearing. These owls may be active during the day but it is still a difficult task trying to spot one as they are very small and tend to wait for their prey to approach them before they pounce. Likewise some owls like the Snowy Owl can be spotted during the day if food availability leans towards this being the best hunting time. Burrowing owls can also be seen around during the day, perching on fences hunting small rodents, reptiles and insects. I hope this post has given you all the information you needed about owls and their sleeping patterns. Now you know that not all owls favour the darkness and you might just be lucky enough to see some of them around as you go about your day!