Barn owl – Tylluan wen
Order Strigiforms
Family Tytonidae
Genus Tyto
Barn owls – Guardians of balance – A shield against invasive rodents.
Grass owls belong to the family Tytonidae ( barn owls and bay owls), and within the genus Tyto, they feature heart shaped facial discs, long legs that appear to dangle in flight, and a preference for tall grass habitats. primarily their diet consists of small rodents, and are often threatened by habitat loss. the common ancestor to these delightful owls are thought to have originated from the Oligocene period, and it believed the modern day genus Tyto descended from a large nocturnal birds in the west indies during the quaternary.
The main characteristic of these owls is having the heart shaped facial disc, which is formed by stiff feathers ,known as the rough, to amplify and locate the source of sounds when hunting, and further adaptions in the wing feathers eliminate sound caused by flying and turbulence aiding both the hearing of this owl species and keeping prey unaware of the owl. Grass owls overall are counter shaded, darker from above paler below, though considerable variation is seen within this species. bay owls closely resemble the barn owls but have a divided facial disc, small ear tufts and tend to be much smaller. Tyto, differ from the typical owls, Strigidae, in structural details relating in particular to the sternum and the feet,
This family of owls is wide ranging although they are not tolerant to severe cold. They are Cosmopolitan and are the most widespread owl species on the globe, found on every continent except Antarctica. they are also absent from the driest desert regions, they live in a wide range of habitats from forests to semi deserts, temperate latitudes to the tropics, preferring to live near agricultural areas with human activity. The majority of the 17 living species are poorly known, and such as that of the Madagascar red owl, which has barely been seen or studied since their discovery. the western barn owl however is one of the well known species in the world, however 5 species of barn owl are threatened and some island species went extinct during the Halocene.
Did you know the Galapagos barn owl, is one of the smallest species of barn owl there is, averaging 26cm, with a 68cm wingspan, and only weighing 260grms. it is an endemic bird of prey, hunting at night for rats, mice and invertebrates. the Galapagos barn owl is one of only two resident and endemic species in the Galapagos the other being the short eared owl, making them an elusive species very rarely seen, however they are vital guardians of the islands ecological balance and protecting the archipelagos unique biodiversity. as night falls this tiny barn owl emerges from volcanic crevices, lava tunnels, to take flight in complete silence, adaptions to allow them to hunt with extraordinary precision in total darkness .a single Galapagos barn owl captures 700 mice per year and a hundred breeding pairs could eliminate almost 200,000rodents annually. providing farmers and ecosystems with a sustainable, cost free form of pest control, this ecological service is particularly critical for the survival of species like the mangrove finch with only as few as 60 individuals left.
As well as their adaptions as silent predators, with a ghostly white appearance, that screech rather than hoot, the barn owls have the best hearing of any animal researched, catching much prey in complete darkness, just by sound alone, a single family of western barn owls can consume over 1000 rodents in a 3 month breeding period alone. during the breeding season barn owls will typically lay 4 – 7 eggs, but have been known to lay up to 14 if the food source is plentiful. known to the hockey stick phenomenon, due to fluctuations in prey numbers due to good or poor seasons, which shows a long period of little or no growth followed by sharp rise, on a graph level this creates a shape in fluctuations that resembles a hocky stick.
Barn owls usually form monogamous pairs however cases of bigamy – with one male pairing with two females has occurred.
Barn owls have particularly large wings relative to their body size, allowing them to quarter slowly over grasslands and fields listening for prey. their flight can be as slow as 2mph to reduce sound and turbulence.
Barn owls have relatively small dark forward facing eyes, and are highly specialized and tubular in shape relative to their head size. designed for superior low light and nocturnal vision, these tubular eyes are held by sclerotic rings in the skull, which prevents eye movement, requiring the barn owl to rotate its head to see around. they have 3 eyelids to protect these specialized eyes. the eye itself also has a reflective layer known as the Tapetum Lucidium which boosts light absorption at night.
Did you know owls once appeared as hawk like
The majority of birds live a diurnal life style, owls however belonging to the order Stigiformes like the Barn owl, have thought to have diverged from their sister group, the Coraciimorphs, this includes mousebirds, woodpeckers and king fishers during the Paleocene, when a radiation of small mammals led to a greater availability of nocturnal prey and to take advantage of this nightly feast . Owls presumably retained predatory features shared with other raptors like eagles and hawks, however at the same time they developed nocturnal traits themselves which developed nocturnally and independently in other birds such as kiwis and iol birds. this culminated in a selection of features that made owls such as the barn owl uniquely suited to fill this niche. which included better night vision, enhanced hearing and feathers for silent flight, a confluence of evolutionary forces. genes involved in sensory perception showed a genome wide signal for positive selection. genes involved acoustic, and light perception, photosensitivity and dim light vision, in the development of the retina and inner ear. sensory perception depending on signaling cascades and circadian rythyms which regulate the bodys internal clock. Evidence for accelerated evolution .and as a surprising result the rod receptor cells in the retinas of nocturnal species such as mice and primates exhibit unusual radially inverted pattern of heterochromatin which acts as a collecting lens increasing light detection in deep layers of the retina. a feature that has not been observed in any bird species to date.
When it comes to attracting potential partners did you know that barn owls rely on an aerial dance called the moth flight. during this beautiful mating ritual, the male will hover directly in front of the female, and literally being much whiter than the female, show off this bright white plumage, feathers on his chest. if the female is sufficiently wooed by his performance she will respond with a snore like call indicating to the male that she is interested and may now bring her a good supply of food such as voles, and with a little luck he will mate with her.
Did you know, unlike many other owls (typical owls) barn owls possess a structure specifically for grooming and preening their feathers, most particularly around their faces and beak, the pectinate claw in barn owls, Tytonidae is a specialist comb like structure with serrations located on the middle talon of their feet. it is belived to remove debris and dander from their newly moulted in feather sheaths, a very distinguishing feature which enhances feather condition for aerodynamic efficiency.
also unlike other bird species the barn owl possess another unique feature for flight control, their sternum has two notches and is fused with the Furcula ( wishbone), their wing bones possess an osseous arch, however they lack the humeroscapular bone found in other raptors. these anatomical peculiarities which are considered adaptions for the barn owls specialized flight and unique wing structure for muscle attachments.
Did you know barn owls possess unique, small dark speckles or spots on their plumage, often referred to as sesame seed markings, and are a key feature for individual identification as they vary between birds .
Barn owls eat mostly voles, shrew ,and mice
Food is swallowed whole, and un digestible parts are regurgitated, cast back through the digestive system through the mouth as tightly moulded pellet, female barn owls will break these super absorbent pellets up to dry in the nest box making use of them as bedding for their eggs and owlets.
Barn owl feathers are super soft, but not waterproof
Barn owls have asymmetrical ear openings, lop sided, one ear opining is higher placed than the other, which helps them to pinpoint exactly where the tiniest sounds are coming from.
a wild barn owl usually consumes around 3-4 voles or shrews a night, that is a staggering 1,460 rodents a year.
Barn owls existed a long time before farmers built barns, and like the Galapagos barn owl, nested in rock crevices and hollow trees. they are a cavity nester, however around 5,500 years ago as soon as farmers began building haystacks and animal barns, the barn owls moved in.
Barn owls spend a lot of time roosting, and need somewhere safe and dry and hidden out of sight to raise a family, however over the last hundred years or so old traditional nest and roost sites have been lost, due to newer buildings, and hollow old trees have been taken down, and church towers and buildings have become netted, so today barn owls live in specially designed, deeper safe nest boxes, an important way to ensure that barn owls survive.
the Barn owl is also known by several other names (regional) , reflecting on this owls lifestyles
the monkey faced owl
the ghost owl
the screech owl
church owl
hissing owl
barn yard owl
straw owl
hobby owl
moggy
screachog (irish)