Barn owl

The barn owl (Tyto alba) is a much loved bird of the British countryside, and indeed of many other parts of the world. It has claims to be among the most widely distributed bird species, and certainly holds this status among the owls. In Britain its numbers appear to be recovering after a period of decline. It is found throughout England and Wales and parts of Scotland and Ireland.

The barn owl’s preferred habitat is open countryside with trees and buildings. It can often be seen flying along field margins, riverbanks and roadside verges.

In recent years, barn owls have moved into towns, especially where open parks and cemeteries provide nesting and feeding opportunities.

Appearance

The barn owl is one of the most distinctive birds, with its heart-shaped face and pure white underparts. It is around 35 centimetres (13.5 inches) in length with a wingspan of some 80 centimetres (31.5 inches). The plumage is orange-buff above with grey mottling. The white underparts are sometimes tinged with buff and marked with dark spots. The spots and mottling are more frequent with female barn owls, although, generally speaking, males and females look alike.

The barn owl’s eyes are small and black, forming a contrast with the white face. The wings taper and the tail is short. The legs are quite long for an owl.

Behaviour

The barn owl is mainly nocturnal, often being seen at dusk as it starts to hunt. However, it will also hunt during the daytime when feeding its young and during the winter. Its flight is wavering and mainly silent, with the wingtips almost meeting on the downbeat.

When agitated it will lower its head, moving it to and fro as it perches.

The barn owl is mostly solitary and roosts in buildings, holes in trees and among rocks. It will stay in the same area throughout the year, although migration in search of food is not unknown in severe winters.

The call is a shrill, draw-out shriek, often uttered in flight, and it also has a variety of hisses, snorts and chirrups. Many people, walking at night, have had the disturbing experience of a barn owl shrieking unexpectedly out of the darkness and swooping just above their head.

Breeding behaviour

Barn owls can raise clutches at any time between March and November and, if the food supply is good, will raise as many as three broods in a year.

The nest is little more than a few pieces of plant material or animal hair gathered in a convenient site such as a roof space, a tree hollow or a rock crevice. The male will select a site and then entice a female to it. Clutch sizes can vary a lot, but four to seven eggs is common. Incubation is by the female, for up to 32 days, with the male feeding her at the nest. When they hatch, the young are fed by their parents until they fledge, which can be for a period as long as 60 days. The young will then scatter into the surrounding area.

Feeding

Barn owls hunt mainly for small mammals such as mice, voles and shrews. However, they will also take small birds, bats, amphibians and large insects. Hunting is by flying low over places where prey is likely to be found and hovering until the moment is right to strike. Alternatively, barn owls will swoop from vantage points such as posts or tree branches. They have excellent hearing and rely on this more than sight to hunt at night. They are therefore able to pounce on prey that is hidden under grass cover or even snow.

Barn owls have a relatively high metabolic rate and so therefore need to maintain a high strike rate.

Preservation status

The barn owl has amber status in the United Kingdom, due to loss of habitat, and even poisoning, in the past and threats to its food supply from modern agricultural practices. However, the bird’s ability to adapt to changing circumstances, plus public awareness, should ensure that its numbers continue to recover.

© John Welford

Coal tit

Several members of the tit family are quite easily confused with each other, and the coal tit (Parus ater) is one of them! In some respects it is not unlike the great tit, and the marsh tit and willow tit are also close look-alikes.

The coal tit is resident throughout virtually the whole of the United Kingdom and it is also widespread throughout Europe, northern Asia and northwest Africa. It is found mainly in coniferous forests, and its absence from certain localities, such as the eastern English fens, is largely due to the lack of such forests in those areas.


Appearance

At around 11 centimetres (4.3 inches) in length, the coal tit is the smallest member of its family. It is noticeable for its large head and stumpy tail. Its short, slender bill is smaller than is seen on blue or great tits, this being so that it can feed easily on conifer seeds.

Its black head and white cheek patches are typical of tits, but the coal tit can be distinguished by the white (or yellowish) stripe on the back of the head. The underparts are light-coloured, with the back grey or even with an olive sheen. The wings are grey-brown with two white bars. Males and females have similar plumage.


Behaviour

Coal tits are as active as blue tits in their feeding habits, but they can also be seen crawling up tree trunks rather like treecreepers. One unusual habit of coal tits is that they will store food for later use.

Preferred food includes insects, larvae and spiders. Adult birds also feed on seeds and nuts, and they are often seen at garden bird tables in winter.

The voice of the coal tit is thin and piping, usually two high repeated notes not unlike those of the goldcrest. A recording of the voice, together with a short video and other information, is available on this page of the RSPB website.


Breeding

Nests are built at the end of April, sites including tree cavities, tree stumps, rock or wall crevices or even holes in the ground. The nest comprises moss with a lining of hairs. A clutch of seven to eleven eggs is incubated by the female alone for 14 or 15 days. Both parents feed the young. The young coal tits leave the nest at 16 or 17 days but stay close to the nest, still fed by their parents, for another two weeks or so.

A second brood is often raised in July. After the nesting period ends, coal tits form flocks to roam the woods and countryside, often with other members of the tit family.

© John Welford

Common gull

The common gull (Larus canus), which is also known as the mew gull, is not as common as its first name suggests, although it is by no means rare. It is widely distributed in Europe and there is also a subspecies that is found in North America. In the United Kingdom it is resident in Scotland and northern England and is a winter visitor in Wales and southern England. There is considerable movement of common gulls around Europe before and after the breeding season, with many of the wintering birds in Britain having come from Scandinavia.


Appearance

At 40-42 centimetres (15.5-16.5 inches) in length, the common gull is considerably smaller than the herring gull but similar to it in overall appearance. Fully mature birds have a blue-grey back, white underparts, black wingtips, greenish-yellow legs and bill (whereas the herring gull has pink legs), and dark eyes. The head and neck are pure white in summer but streaked with grey in winter.

Male and female common gulls are similar to each other in appearance.


Habitat

Common gulls breed either on the coast or inland, the latter including moorland, bogs, marshes, lakes and rivers. In the winter they are often seen on farmland and in urban environments such as playing fields and reservoirs.


Behaviour and feeding

The common gull is a sociable bird that will feed and roost alongside other gull species outside the breeding season, and may also share breeding colonies with other gulls or terns.

Food for the common gull varies between the seasons, being mainly worms, insects, fish, small mammals and the eggs and young of other bird species in summer, and invertebrates, fish and crustaceans in winter. As well as “following the plough” for worms, the common gull also frequents rubbish tips, especially during harsh winters. They will eat carrion as well as live prey and will also rob other birds of their food.

The common gull gets its name of “mew gull” from its high-pitched mewing call.


Breeding

Birds arrive at their nesting grounds already paired, in March or early April.

Common gulls can build nests in various locations, including clifftop ledges, on the ground, in vegetation, or on roofs. They have even been known to nest in trees. Both partners build the nest, from whatever vegetation is availa80,695,551ble, including seaweed, although the female does most of the work with the materials being fetched by the male.

A clutch of two to four eggs is laid, with both adults incubating them in turn for up to 28 days. The young birds leave the nest within two days, although they do not wander far. Food is brought to them by both parents, the chicks taking it from the adult birds’ beaks. After 20 days the young gulls are able to find their own food, but it is not until they are 35 days old that they can fly and are fully independent.


Conservation

The common gull is not regarded as being a species in danger and is not therefore the target of any conservation measures. Future threats might come from moves to drain inland marshes and develop other environments where they tend to winter.

© John Welford

Avocet

The avocet (Recurvirostra avosetta) is a fascinating and easily-recognised bird which has a unique claim to fame due to having been chosen as the logo of the RSPB (Royal Society for the Protection of Birds). This came about because of the success of conservationists in saving the bird from extinction in the UK, where it now has legal protection from harm and disturbance.

The avocet is a wader that inhabits shallow waters in creeks, estuaries and coastal lagoons. It is fairly common on the coasts of continental Europe, both north and south, but had been absent for British waters for around a century before wartime conditions (1939-45) gave it a chance to re-colonise. It now breeds in quite large numbers in the UK, particularly in south-east England at places such as the RSPB’s Minsmere reserve in Suffolk. Large numbers have taken to wintering in suitable places along the south coast, particularly Poole Harbour and the Exe estuary in Devon.

The avocet is a large wader, up to 45 centimetres (17.5 inches) long, with long blue-grey legs and a very distinctive long bill that turns up at the end. The body is mostly white, with black on the head and nape of the neck. The wings are black and white, which gives the bird a piebald appearance when walking or in flight. Males and females have similar plumage. When flying, the legs trail behind.

The avocet feeds mainly on small water creatures such as crustaceans that live in the mud below shallow, brackish water. The avocet stamps its feet on the mud to disturb the creatures, which are then taken by the bird as it sweeps its bill from side to side as it steps forward, looking not unlike someone vacuuming a carpet. This highly unusual feeding methods accounts for the shape of the bill, the “business end” of which is parallel to the mud surface as the avocet feeds.

However, avocets can also feed in deeper water, upending themselves like ducks or taking food from the surface. When food is plentiful, many birds will gather in large flocks in the shallow water or on mudflats.

Avocets also tend to breed in colonies, although these are generally not particularly large or dense. Pairs form after an elaborate mating display, and both birds prepare a nest consisting of a depression in the grass or mud close to the water’s edge and lined with a small amount of grass or twigs. This nesting behaviour is one reason why avocets need protection in order to survive in areas close to human habitation. A motorboat speeding close to the shore could easily swamp a nest, but then so could an unusually high tide coupled with storm conditions.

Avocets lay three or four eggs, one or two days apart, any time from mid-April to late June. Both parents incubate the eggs, which take up to 25 days to hatch. When hatched, the chicks are mobile within only a few hours and are able to follow the adult birds into the water and start feeding for themselves. However, they rely on their parents’ protection for a long time, even after they have fledged at around 40 days.

Another reason why avocets have found it hard to maintain their populations is that many chicks do not survive to adulthood, particularly if food is scarce or there is bad weather at the wrong time. Avocets may lay a second clutch of eggs if the first is lost, but not if the chicks, once hatched, fail to thrive. Given that the birds only breed from the age of two years, and the average lifespan is seven years, that does not give the birds many opportunities to increase their numbers if broods are lost in successive years.

One factor that may help avocets, and other wetland birds, to continue to increase in numbers is the policy of allowing sea walls in parts of eastern England to be breached and for formerly reclaimed land to return to wetland status. The creation of avocet-friendly environments should ensure that this attractive and unusual bird will still be around for future generations of bird-lovers to marvel at.

© John Welford

Boat-billed heron

The boat-billed heron (Cochlearius cochlearius) is the only member of the Cochlearius genus within the Tigrisomatinae subfamily of herons (Ardeidae). It has proved difficult to classify due to having features that seem to set it apart from other herons.

The boat-billed heron, otherwise known simply as the boatbill, inhabits freshwater mangrove swamps in Central and South America, anywhere from Mexico to Peru and southern Brazil. It is largely nocturnal, spending the daytime hidden in the mangrove thickets. It is therefore rarely seen and not everything is known about its habits.


Appearance

It measures about 22 inches in length, being mostly grey above and brownish below. It has black patches on its head, flanks and back and broad black crest feathers. The face and throat are white and the wings are pale grey.

However, the most unusual feature of the boat-billed heron is, not surprisingly, its bill, which is broad and scoop-shaped, three inches long and two inches wide. This is associated with a wide mouth, which in turn makes the head broad and the eyes, which are large to aid night vision, set wide apart. The boat-billed heron shares these features with no other heron, which is why its classification has been problematic.


Behaviour and feeding

Because it is nocturnal, and inhabits remote areas, observations of the boat-billed heron when feeding have been few and far between, so there is some speculation as to what advantage the birds gain from having such a strange-shaped bill. It is reported that its diet consists of worms, crustaceans, fish, amphibians, water snakes and small mammals such as mice. However, it is not clear how its bill would be useful for catching fast-moving prey such as fish or mice, as it would seem to be more fitting for sifting the mud of the mangrove swamps for worm and insects.

The boat-billed heron has a harsh frog-like croak and a high-pitched whistle. It also claps and rattles its bill, as some storks do.


Breeding

Pairs of boat-billed herons sometimes nest alone and sometimes in small colonies, occasionally alongside night herons. Pairs form after a mating ritual that involves the male bird displaying its crest feathers and offering sticks to the female. Both birds clatter their bills a lot at such times. Pair bonds are reinforced with mutual preening.

The nest is a shallow construction of sticks in a mangrove tree. Three or four blue-white eggs are laid, these being incubated by both partners, who also share in feeding the chicks, which hatch after about 25 days. The young birds stay at the nest for up to eight weeks.

© John Welford

Caspian tern

The Caspian tern (Hydroprogne caspia or Sterna caspia) is widely distributed around the world, being found on every continent except Antarctica. Its numbers appear to be increasing across much of its range, so it is fortunate to be regarded as a species of “least concern” by BirdLife International.

Depending on its location it is either sedentary or migratory. North American birds migrate between the breeding grounds of the Great Lakes and northern coasts to the southern coasts and the Caribbean, while in Europe the movement is between the coasts of the Baltic and Black Seas and tropical Africa.


Appearance

The Caspian tern is the largest species of tern, having an adult body length of 48-56 centimetres (19-22 inches) and a wingspan of 127-140 centimetres (4-4.5 feet), which is greater than that of the common gull.

The body is white with the back and wings being pale grey. The cap of the typically tern-like flat head is black but the Caspian tern is particularly noticeable from its large bright red bill with a dark tip. The legs and feet are black. The tail has a shallow fork. In juvenile birds the plumage is greyer, the bill more orange than red and the legs paler. Male and female Caspian terns are similar to each other in appearance.


Habitat

The Caspian tern is generally a coastal species, preferring sheltered sea coasts, estuaries, harbours and the like. During the breeding season it prefers sandy or shingle beaches or sparsely vegetated rocky environments, often on remote offshore islands. It is only likely to be seen inland during migration.


Behaviour and Feeding

Outside the breeding season the Caspian tern is not highly gregarious, although it can form flocks during migration. Groups of Caspian terns may sometimes be seen feeding together at places where food is plentiful, or at night roosts.

Food is mainly medium-sized fish (such as herring), although invertebrates and the eggs and young of other bird species are sometimes taken. Caspian terns are unusual among tern species in that they will also eat carrion.

The flight of the Caspian tern is not unlike that of gulls, with slow ponderous wingbeats. When feeding they will fly not far above the water, hover for a few seconds, then dive to take a fish.

The voice of the Caspian tern is a deep hoarse “kree-ark”. Young birds will call with a squeaky “wee-vee”.


Breeding

Caspian terns return to their breeding grounds in April or May (assuming a Northern Hemisphere population). Breeding colonies can be large, but they are also found breeding as lone pairs or scattered among colonies of other species.

The nest is a scrape in the ground with only a few pieces of plant matter. The usual clutch comprises two eggs, laid in May or June, which both partners incubate for 20-22 days. Shortly after hatching, the chicks disperse to hide in neighbouring vegetation, with food being brought to them by their parents. Caspian terns have been noted to fly up to 40 miles from the nest site on foraging trips.

The young are able to fly and fend for themselves at about 30-35 days after hatching.


Conservation

As noted above, the Caspian tern is under no overall threat globally, although this is not always true of local populations. Threats come mainly from habitat loss due to human activity, with rising sea levels being a concern in some areas. The use of fertilisers and pesticides, the residues of which can poison fish, can affect the breeding ability of birds which feed on those fish, the Caspian tern included.

© John Welford

Chestnut-tailed thornbill

The chestnut-tailed thornbill (Acanthiza uropygialis) is an Australian bird that is also known as the chestnut-rumped thornbill and chestnut-rumped tit-warbler. It is found in dry inland scrub country south of the Tropic of Capricorn.

It is a small bird that is not quite four inches in length. Males and females are similar in appearance, which includes upperparts that are greyish brown and underparts that are a dull greyish white. The wings are dusky brown, the tail black with a white tip and the rump a rich chestnut colour. There are whitish freckles on the forehead and ear coverts. The bill is dark brown and the eyes are white. The legs are almost black.

It has a long, animated song and, when in flocks, produces a steady twittering sound.

The chestnut-tailed thornbill is usually found in groups, especially outside the breeding season. It spends much of its time on the ground or lower levels of scrub vegetation, feeding on insects.

Breeding takes places from August to December, when two broods are usually raised, two to four eggs being laid each time. A domed nest is built, with a side entrance, often in a hollow on a dead tree or behind loose bark. The nest can be at any height from three to eighteen feet up a tree.

The nest consists of grass and strips of bark bound together with cobwebs and lined with fur, hair and feathers.

© John Welford