With their big, round heads and disproportionately large eyes, owls are unmistakable creatures. Mainly nocturnal1, they are found on every continent with the exception of Antarctica, and their distinctive appearance and sound makes them one of the best known orders in the animal kingdom. Across the world, they have become birds of folklore and legend, and in Britain the screech of a barn owl and the 'tu-whit, tu-whoo' of a tawny owl are among the most obvious calls of any bird - when one gets to know them.
All owls belong to the order Strigiformes but are divided into two families; the Tytonidae (Barn Owls) and Strigidae (all the others). They are known as 'birds of prey' (or 'raptors') as they feed exclusively on other creatures. Most British owls are nocturnal, though the barn owl is described as 'crepuscular2'. The short-eared owl is active at all times, being described variously as 'diurnal3' and crepuscular as well as nocturnal; however, it is clear that the short-eared owl is the only one to be particularly active in the daytime.
Finding owls can be difficult. They do regurgitate small pellets of indigestible bones, fur and feather which can be found below their nests or perches, but the birds themselves are difficult to see as they are well camouflaged. One way to spot them is by using an owl whistle, which can be bought with different sounds for various species. By imitating the sound (often taking considerable practice) territorial owls can be 'called in', as they will often investigate intruders.
Many superstitions are associated with owls in general, often relating to the birds' extraordinary abilities. Popular myth suggested that if you were to walk around and around a tree with an owl in, it would watch you so intensely that it would eventually wring its own neck. In fact, owls cannot turn their heads all the way round, but are amazingly quick in snapping their heads around through almost 360° to keep their subject in view.
Owls' eyesight is also legendary, and eating owl eyes was believed to imbue the ability to see in the dark. To most readers, carrots will seem an easier and more attractive proposition. Owl meat and broth has also been used variously as a cure for whooping cough, as an aphrodisiac and as a cure for rheumatism and seizures.
Shakespeare uses an owl as one of the omens of doom in Julius Caesar, where it sits:
Even at noonday upon the market-place
Hooting and shrieking.
Owls were also frequently associated with witches and warlocks, appearing regularly as 'familiars' or mystical companions. Although rather macabre, it was believed that nailing a dead owl to your door would protect you from evil spirits.
In Wales, it was often said that if an owl was heard amongst the houses of a village, then a girl had lost her virginity. Owls were also associated with Blodeuwedd, the goddess of betrayal, in the ancient Welsh story 'The Mabinogion'.
Numbers of all our owls have suffered a decline since the early 20th Century. So what factors precipitated this? Loss of habitat - through development and intensive farming - has been a key issue, and it has been estimated that between 3,000 and 5,000 barn owls are killed on Britain's roads each year, a significant barrier to population recovery. Converting old barns into luxury cottages has severely limited the available nesting sites for owls. Certain owls (particularly barn owls) were seriously affected by changes in farming practices. Farmers correctly held the view for centuries that owls were good at keeping rodent populations low, and despite the 'evil spirit' reputation, often built boxes for owls to roost in outhouses and barns. Great news for owls, until the pesticide revolution in the mid-20th Century meant less need for owls and less food for owls. The populations of many owls declined sharply, especially when it was found that rodenticides made their way into the owls' bodies through their food, with very harmful effects4.
Owl Species in the UK
Barn Owl Tyto alba
With its white, ghostlike appearance, banshee-like screeching call and heart-shaped face, the barn owl is one of Britain's most distinctive birds. Active around twilight, it can usually be found nesting in hollow trees5 or abandoned buildings, and its preferred habitats are farmland, open woodlands, marshes and heaths. A joint 1995-7 survey by the BTO6 and the Hawk and Owl Trust estimated the UK population to be around 4,000 breeding pairs, and there are estimated to be a further 750 pairs in Ireland, where numbers of the Scréachóg reilige7 have dropped by over 60% in the last 25 years.
Barn owls have long been feared by the British population, until quite recent times. Rather than crows or ravens, it was barn owls that were described as the 'bird of death' by poets William Wordsworth and Robert Blair. The barn owl was even reputed to be able to predict the weather; its screeching indicating a change in the weather, for good or bad. In America, the Newuk tribe believed that evil people would turn into barn owls when they died. And in the UK and Australia, the bird's strange luminosity gave rise to legends of the will-o'-the-wisp (aka jack-o'-lantern, min-min light, or dead man's campfire), which variously spirited away travellers, children or the sick.
The Barn Owl Trust is a national charity dedicated to conserving barn owls.
Little Owl Athene noctua
The little owl is Britain's smallest owl, just 8 inches (22cm) tall and with a wingspan of around 22 inches (55cm). They were present in Britain during the last two ice ages (fossil records exist from 500,000 years ago in Derbyshire, amongst other places), but after this time became infrequent seasonal visitors. Also known as the Dutch or French owl, it was reintroduced from Europe in the late 19th Century and there are now around 9,000 pairs spread across England and Wales, with a few in the southern regions of Scotland. Only four records exist from Ireland, where it was never introduced.
The popular image of the 'wise old owl' is attributed to the ancient Greeks, who associated the little owl with Athene, the goddess of wisdom8. Thanks to this association, it is believed that the little owl was the first bird in the world to be protected by law, and the Acropolis itself was home to large numbers of them! It was used as a symbol by the Greek army, and if one flew over the troops before battle, victory was considered assured. The Romans continued many of the Greek beliefs by simply transferring them to their equivalent god, Minerva.
In Yorkshire, it was believed that dried salted little owl flesh could be used to cure gout.
Long-eared Owl Asio otus
Estimates of numbers of long eared owls vary widely, as it is probably the hardest of our resident owls to locate; however, the best estimates put the population at around 4,000 to 5,000 pairs, 2,000 of which are in Ireland - making it Ireland's most common owl. It is prevalent roughly north of a line from Aberystwyth to Kent, although migratory owls can be seen countrywide, often visible on the coast even in daylight. It prefers conifer plantations which have plenty of open ground nearby.
Its ears are not in fact ears at all, but long tufts of hair; like other owls, its ears are holes well hidden on the side of the head.
Short-eared Owl Asio flammeus
Strangely nomadic, the short-eared owl is the least numerous of British species, with an estimated 2,000 breeding pairs. They are most numerous in the north of England and in Scotland, but in the winter can be found in most regions of the British Isles. They can also be found in Ireland, where they are not considered resident, but are occasionally recorded. Nesting on the ground in open areas such as heaths, sand dunes, marshes and wetlands, they often share their roosts with other short-eared owls. Hunting mainly for small mammals like voles, but also large insects and small birds, it is the only British owl that is at its most active during daylight hours.
Tawny Owl Strix aluco
The tawny (or woodland) owl is the most common in Britain (despite being entirely absent from Ireland), with numbers estimated to be a healthy 20,000 - it is also the most common in Europe. It is responsible for the classic 'tu-whit, tu-whoo' sound of owls at night - although, in reality, it is the male that makes a long rambling 'whooo' sound while the female provides a sharp 'ke-wick' reply9. They generally mate for life (although some males have been known to have more than one mate at the same time), and also occupy roughly the same territory year after year.
In the daytime, tawny owls roost on the branch of a tree, and frequently have their position given away by being 'mobbed' by much smaller birds! They are usually unruffled by this behaviour, and often sleep right through it. Those owls which live in woodland exist on a diet of voles, small birds and mice10, and if the weather is bad will frequently come down to ground level to scratch around for worms, insects and beetles. They have also adapted well to city life, even taking goldfish from garden ponds!
Tawny owls were hunted by gamekeepers until the early part of the 20th Century, but their easy adaptation into urban environments ensured their survival and helped them flourish. In 2005, the BTO began a survey to provide reliable data on tawny owl numbers, believing that they had dropped by a third in ten years. Of course, there are problems associated with counts of nocturnal birds, but the warning is certainly one to be heeded.
There have also been recorded sightings of two other, non-resident species of owls in Britain.
Eurasian Eagle Owl (Bubo bubo)
The world's largest owl, weighing 4kg and with an impressive two metre wingspan, has occasionally been reported in Britain. Though many of these sightings are of birds that have escaped from collections or have been released illegally, evidence is mounting that they may have crossed the Channel from mainland Europe, where they are becoming common. What is for certain is that a pair have been breeding in Yorkshire since 1997 (see BBC News for the full story), raising 23 youngsters, one of which was found dead in Shropshire.
While the RSPB and the British Ornithologists Union maintain that the bird is an 'alien' species, there is evidence that the bird was once resident in the UK and was hunted to extinction sometime in the 19th Century. The debate over the presence of the eagle owl in Britain - and not least its effect on other wildlife - is likely to continue.
Snowy Owl (Bubo scandiaca)
As much as Harry Potter's friend Hedwig may have caught the imagination of Britain's children, the snowy owl is not resident here. There are occasional sightings (three per year on average, according to the BTO), the vast majority from the north of Scotland. Again, many individuals may have been released deliberately or accidentally. While the bird lives predominantly around the Arctic Circle, it is believed that they have sometimes found their way from Scandinavia by mistake and simply not been able to find a passage back. The last known resident pair lived on the Shetland Island of Fetlar until 1974, when the last male died, but in January 2005 there was much excitement when a male turned up on the island of Coll in Argyll - the first record there since 1891! Two days later a young female was found on Tiree, a neighbouring island, and there is a small hope that the two may breed.