Owl hole

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An Owl hole at Lugton Ridge Farm, Auchentiber. Owl Hole Lugton Ridge.JPG
An Owl hole at Lugton Ridge Farm, Auchentiber.

An owl hole is a structural entrance built into buildings (such as mills and barns) to allow predatory birds, typically Barn Owls ( Tyto alba ), to enter. The birds prey on farm vermin, and therefore benefit the human owner of the structure in a symbiotic relationship.

Contents

History

The Barn Owl feeds primarily on small vertebrates, particularly rodents. Studies have shown that an individual Barn Owl may eat one or more rodents per night; a nesting pair and their young can eat more than 1,000 rodents per year and have been referred to as 'nature's mousetraps'. [1] Locally superabundant rodent species in the weight class of several grams per individual usually make up the single largest proportion of prey. Barn Owls consume more rodents than possibly any other creature. This makes the Barn Owl one of the most economically valuable wildlife animals to farmers, millers, etc. Farmers and others found these owls effective in keeping down rodent pests, and they encouraged Barn Owl habitation by providing nest sites. [1] In the few months between hatching and fledging a clutch of six owlets can consume up to 70 pounds (32 kg) of rodents. [2]

Vertebrate subphylum of chordates

Vertebrates comprise all species of animals within the subphylum Vertebrata. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates include such groups as the following:

Rodent Diverse order of mammals

Rodents are mammals of the order Rodentia, which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents ; they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments.

With the advent of modern pesticides the perceived value of biological control has dramatically decreased to the point that few owl holes are still in active use. Many of the holes have been blocked up and landing platforms broken off.

Design

First used at the end of the 17th century, [3] these were often positioned on the gables end of buildings owl holes were usually placed under the eaves. The perch or landing platform was made from stone or wood and usually sloped slightly downward to prevent rain water from entering the building. The entry holes are usually oblong and of a size 6 to 9 inches (152–228 mm) [3] that permits a single bird to enter with space for a safe landing and passage to the interior whilst at the same time excluding larger predators. [1] Owl holes without landing platforms had grooves or rough surfaces beneath the hole to aid grip. On wooden buildings circular examples are sometimes found. [4] The openings usually faced onto open ground so that they could be easily seen by barn owls seeking nesting sites. [1] Owl holes also assisted ventilation within barns and provided for some extra illumination.

Some examples found on the gable ends of wooden barns are very ornate and may be the 'signatures' of the craftsmen who built the barns, coupling this with a practical function of ventilation and as owl holes.[ citation needed ] Owl holes are sometimes found in association with dovecots as pigeons are not generally a prey species for barn owls.[ failed verification ]

Dovecote structure intended to house pigeons or doves

A dovecote or dovecot or doocot is a structure intended to house pigeons or doves. Dovecotes may be free-standing structures in a variety of shapes, or built into the end of a house or barn. They generally contain pigeonholes for the birds to nest. Pigeons and doves were an important food source historically in the Middle East and Europe and were kept for their eggs and dung.

Distribution

In Scotland owl holes were a common feature of old farms and mills, such as Roughwood Farm and Dalgarven Mill.

The Lands of Roughwood castle in North Ayrshire, Scotland, UK

Roughwood once Ruchwood is a farm, originally a estate, possessing at one time a small tower castle. Roughwood is situated near to the town of Beith in North Ayrshire, Scotland; the lands lay within the old Lordship of Giffen.

Dalgarven Mill – Museum of Ayrshire Country Life and Costume

Dalgarven Mill is near Kilwinning, in the Garnock Valley, North Ayrshire, Scotland and it is home to the Museum of Ayrshire Country Life and Costume. The watermill has been completely restored over a number of years and is run by the independent Dalgarven Mill Trust.

Owl holes were found in Wales, a 'triangular' example survives at Llangattock in Glamorgan. [5]

In England an example is to be found on an old pumping mill in Norfolk, old barns in Yorkshire, etc. [6]

In Germany these structures are known as 'Eulenloch' ("owl-hole"). [7]

Examples are recorded from Ontario in Canada [5] and the USA. [4]

Micro-history

In Hallstatt at the foot of the Echernwand, a trapeze-shaped opening is visible in the rock face. The hole in the cliff has been known as the "Eulenloch" (owl hole). [8]

Related Research Articles

Common buzzard Species of bird of prey

The common buzzard is a medium-to-large bird of prey which has a large range. A member of the genus Buteo, it is a member of the family Accipitridae. The species lives in most of Europe and extends its range into Asia, mainly western Russia. Over much of its range, it is a year-round resident. However, buzzards from the colder parts of the Northern Hemisphere as well as those that breed in the eastern part of their range typically migrate south for the northern winter, many culminating their journey as far as South Africa. The common buzzard is an opportunistic predator that can take a wide variety of prey, but it feeds mostly on small mammals, especially rodents such as voles. It typically hunts from a perch. Like most accipitrid birds of prey, it builds a nest, typically in trees in this species, and is a devoted parent to a relatively small brood of young. The common buzzard appears to be the most common diurnal raptor in Europe, as estimates of its total global population run well into the millions.

Owl order of birds

Owls are birds from the order Strigiformes, which includes about 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers adapted for silent flight. Exceptions include the diurnal northern hawk-owl and the gregarious burrowing owl.

Barn owl A common cosmopolitan owl

The barn owl is the most widely distributed species of owl and one of the most widespread of all birds. It is also referred to as the common barn owl, to distinguish it from other species in its family, Tytonidae, which forms one of the two main lineages of living owls, the other being the typical owls (Strigidae). The barn owl is found almost everywhere in the world except polar and desert regions, in Asia north of the Himalaya, most of Indonesia, and some Pacific islands.

Long-eared owl species of bird

The long-eared owl, also known as the northern long-eared owl or, more informally, as the lesser horned owl or cat owl, is a medium-sized species of owl with an extensive breeding range. The scientific name is from Latin. The genus name Asio is a type of eared owl, and otus also refers to a small, eared owl. The species breeds in many areas through Europe and Asia, as well as in North America. This species is a part of the larger grouping of owls known as typical owls, of the family Strigidae, which contains most extant species of owl.

Northern hawk-owl species of bird

The northern hawk-owl is a medium sized true owl of the northern latitudes. It is non-migratory and usually stays within its breeding range, though it sometimes irrupts southward. It is one of the few owls that is neither nocturnal nor crepuscular, being active only during the day. This is the only living species in the genus Surnia of the family Strigidae, the "typical" owls. The species is sometimes called simply the hawk owl; however, many species of owls in the genus Ninox are also called "hawk owls".

Great horned owl species of bird

The great horned owl, also known as the tiger owl or the hoot owl, is a large owl native to the Americas. It is an extremely adaptable bird with a vast range and is the most widely distributed true owl in the Americas. Its primary diet is rabbits and hares, rats and mice, and voles, although it freely hunts any animal it can overtake, including rodents and other small mammals, larger mid-sized mammals, birds, reptiles, amphibians, and invertebrates. In ornithological study, the great horned owl is often compared to the Eurasian eagle-owl, a closely related species, which despite the latter's notably larger size, occupies the same ecological niche in Eurasia, and the red-tailed hawk, with which it often shares similar habitat, prey, and nesting habits by day, thus is something of a diurnal ecological equivalent. The great horned owl is one of the earliest nesting birds in North America, often laying eggs weeks or even months before other raptorial birds.

Eastern screech owl species of bird

The eastern screech owl or eastern screech-owl is a small owl that is relatively common in Eastern North America, from Mexico to Canada. This species is native to most wooded environments of its distribution, and more so than any other owl in its range, has adapted well to manmade development, although it frequently avoids detection due to its strictly nocturnal habits.

Spotted owlet species of bird

The spotted owlet is a small owl which breeds in tropical Asia from mainland India to Southeast Asia. A common resident of open habitats including farmland and human habitation, it has adapted to living in cities. They roost in small groups in the hollows of trees or in cavities in rocks or buildings. It nests in a hole in a tree or building, laying 3–5 eggs. They are often found near human habitation. The species shows great variation including clinal variation in size and forms a superspecies with the very similar little owl.

Australian masked owl species of bird

The Australian masked owl is a barn owl of Southern New Guinea and the non-desert areas of Australia.

Pellet (ornithology) material regurgitated by certain birds

A pellet, in ornithology, is the mass of undigested parts of a bird's food that some bird species occasionally regurgitate. The contents of a bird's pellet depend on its diet, but can include the exoskeletons of insects, indigestible plant matter, bones, fur, feathers, bills, claws, and teeth. In falconry, the pellet is called a casting.

Tropical screech owl species of bird

The tropical screech owl is a small species of owl in the family Strigidae.

African grass owl species of bird

The African grass owl is a species of owl in the barn owl family, Tytonidae.

Ashy-faced owl species of bird

The ashy-faced owl is a species of owl in the family Tytonidae. It is found in Haiti and the Dominican Republic. Its natural habitats are subtropical or tropical dry shrubland, subtropical or tropical high-altitude shrubland, and, now, heavily degraded former forest.

Tasmanian masked owl species of bird

The Tasmanian masked owl is a bird in the barn owl family Tytonidae that is endemic to the island state of Tasmania, Australia. It is the largest subspecies of the Australian masked owl, the largest Tyto owl in the world, and is sometimes considered a full species. The subspecific name castanops, meaning “chestnut-faced”, comes from the colouring of the facial disc. It was first described by John Gould, who wrote about it in his “Handbook to the Birds of Australia” as:

”…a species distinguished from all the other members of its genus by its great size and powerful form. Probably few of the Raptorial birds, with the exception of the Eagles, are more formidable or more sanguinary in disposition."

"Forests of large but thinly scattered trees, skirting plains and open districts, constitute its natural habitat. Strictly nocturnal in its habits, as night approaches it sallies forth from the hollows of the large gum-trees, and flaps slowly and noiselessly over the plains and swamps in search of its prey, which consists of rats and small quadrupeds generally.”

Plucking post

A plucking post is a raised structure such as a tree stump which is used regularly by a bird of prey to dismember its prey, removing feathers and various other inedible parts before eating it.

Tawny owl species of bird

The tawny owl or brown owl is a stocky, medium-sized owl commonly found in woodlands across much of Eurasia. Its underparts are pale with dark streaks, and the upperparts are either brown or grey. Several of the eleven recognised subspecies have both variants. The nest is typically in a tree hole where it can protect its eggs and young against potential predators. This owl is non-migratory and highly territorial. Many young birds starve if they cannot find a vacant territory once parental care ceases.

Eastern barn owl species of bird

The eastern barn owl is usually considered a subspecies group and together with the American barn owl group, the western barn owl group, and sometimes the Andaman masked owl make up the barn owl. The cosmopolitan barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The eastern barn owl is native to southeast Asia and Australasia.

Western barn owl

The western barn owl is usually considered a subspecies group and together with the American barn owl group, the eastern barn owl group, and sometimes the Andaman masked owl make up the barn owl. The cosmopolitan barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The western barn owl is native to Eurasia and Africa.

American barn owl species of bird

The American barn owl is usually considered a subspecies group and together with the western barn owl group, the eastern barn owl group, and sometimes the Andaman masked owl, make up the barn owl, cosmopolitan in range. The barn owl is recognized by most taxonomic authorities. A few separate them into distinct species, as is done here. The American barn owl is native to North and South America, and has been introduced to Hawaii.

References

Notes
  1. 1 2 3 4 University of Florida Archived 2014-03-07 at the Wayback Machine Retrieved : 2012-05-16
  2. Building Barn Owl Boxes Retrieved : 2012-05-16
  3. 1 2 Peters, Page 16
  4. 1 2 Owl Holes Retrieved : 2012-05-16
  5. 1 2 Glamorgan Walks Retrieved : 2012-05-17
  6. Wharfedale Heritage Retrieved : 2012-05-16
  7. Eulenloch Retrieved : 2012-05-16
  8. About Hallstatt Retrieved : 2012-05-16
Sources

External sources