Long-tailed tit

Name and taxonomy

Carl Linnaeus described the bird in 1758 as Parus caudatus. He did not coin that name, because Conrad Gessner had used it in 1555. Ulisse Aldrovandi used it in 1599, and Francis Willughby in 1676. Willughby gave the English form as the long tail'd titmouse. The Latin word caudatus simply means tailed. Aristotle used aegithalos for small European tits, and the genus name comes from him.

An older English nickname for the bird was the bum-towel, after the shape of the tail. The species was first placed with the true tits in the genus Parus. It now sits in a family of its own, the Aegithalidae. It is the only member of that family in northern Eurasia. Seventeen subspecies are recognised, and they blend into one another where they meet. Older schemes sorted those forms into three groups. The Avilist order now lists the European forms first and the east Asian ones after.

Evolution and relatives

The bushtit family holds 13 species in three genera. All but one of them live in Eurasia. The genus Aegithalos holds nine species, and Leptopoecile holds two tit-warblers. The American bushtit of western North America is the only member outside Eurasia. The long-tailed tit has the widest range in the family. The pygmy bushtit is the opposite case, confined to mountains in western Java.

The silver-throated bushtit of China was once counted as the same species. Distinct plumage and clear genetic differences later split it off. It lives in the Yangtze and Yellow River basins, with a pocket in Yunnan. Every bird in the family builds a domed or hanging bag of cobweb and lichen. Helpers at the nest are known in at least four of the species, so the habit is probably old.

Appearance

The bird appears to be a small ball with a stick attached. The tail roughly doubles the length of the body. The back and wings are black, and the underside is white or dusky pink. Grey and pink wash over the shoulders and flanks. The bill is tiny and triangular. Male and female look the same.

Northern birds are paler and carry a clean white head. Southern birds have broad dark stripes above the eye. An adult measures 13 to 15 cm and weighs 7 to 9 g. The wings span 16 to 19 cm. A young bird moults into adult plumage before its first winter. That moult starts very soon after it leaves the nest. Animal Diversity Web gives an average length of 14 cm for the species.

Habitat and range

The long-tailed tit is spread across temperate Europe and the Palearctic. The range runs north into Scandinavia and south to the Mediterranean. It reaches east through Asia as far as China and Japan. It likes deciduous and mixed woodland with a good shrub layer. Woodland edges suit it better than deep forest. It is uncommon in pure conifer woods. Animal Diversity Web records it from nearly all of Europe, apart from the far north.

Scrub, heath with scattered bushes, hedges, riverside trees, parks and gardens all hold birds. Winter flocks favour oak and ash woodland, with sycamore in some districts. Nesting draws the birds into scrub above all. Most nests sit under 3 metres in a thorny bush. Hard winters and a lack of the right scrub set the northern limit. GBIF records the species from 73 countries and territories.

Diet and feeding

The long-tailed tit eats insects and spiders through the whole year. The eggs and caterpillars of moths and butterflies are the favourite food. Small spiders and aphids also make up a large share. The bird takes a little plant food, mainly seeds, in autumn and winter. It has begun to visit garden seed feeders in the colder months.

A flock works its way through twigs and foliage, picking prey off the surface. Birds hang upside down and swing from thin branches to reach it. The whole group moves fast and keeps calling as it goes. Feeding in a flock probably finds more food and spots more danger. That habit shapes the woodland the birds pick for the winter. In autumn and winter the flock adds a few seeds to the insect diet.

Behaviour and social life

Outside the breeding season the birds live in tight flocks of six to seventeen. A flock is a family: parents, the young of the last season, and any adults that helped. Each flock holds a winter territory and defends it against the neighbours. Cold is thought to be the reason for the flock. The birds huddle in a row at night, and huddling carries more of them through a frost.

Rank inside the flock decides who gets the warm inside places in the roost. The flocks break up when the breeding season starts. Males stay inside the old winter territory. Females tend to wander into the territory next door. In June and July the winter flocks form again on the same ground.

Close relatives live side by side, which brings a risk of inbreeding. The birds avoid it by telling kin from non-kin before they pair. They appear to make that judgement by voice. As with other cooperative breeders, the calls of a family probably sound alike. The whole pattern is called cooperative breeding. A helper gains because the chicks it feeds carry many of its own genes.

Communication and senses

A flock calls without pause as it moves, so people hear it before they see it. There are three main calls. One is a single high pit. One is a triple trill, written as eez-eez-eez. The third is a rattling schnuur.

The calls speed up and get louder when the flock crosses open ground. A bird that falls behind calls harder until it catches up. Voice also carries the family badge that stops a bird pairing with a relative. A failed breeder finds a relative's nest by listening for that voice. Sight probably matters too, because the birds glean prey from thin twigs.

Reproduction and life cycle

Nest building starts in late February or early March. The finished nest is a stretchy bag, entered by a small round hole near the top. It hangs low in gorse or bramble, or high in the fork of a tree. Moss and spider silk give it its strength. The tiny moss leaves catch on the silk like the two halves of a hook fastener. A typical nest uses over 6000 separate pieces.

Hundreds of pale lichen flakes cover the outside and hide the nest. More than 2000 downy feathers line the inside for warmth. In Britain and Ireland the first clutch comes between late March and late April. A clutch holds six to eight eggs, and larger counts are recorded elsewhere. The female alone incubates for 15 to 18 days while the male brings her food. The chicks stay in the nest about 16 days.

Only one brood is raised each year. About half of all nests have at least one helper. Helped nests do better, through more food and better defence. Most wild birds live only 2 to 3 years. The record for the species is 11.1 years. A pair that fails after early May does not try again that season.

Predators and threats

Jays and crows rob most of the nests. Only about 17 percent of nests succeed. A nest that escapes a raid has a 97 percent chance of working out. Small hawks take adult birds. The plumage is cryptic, and a flock keeps many eyes on watch.

Cold is the greater danger to so small a bird. A long frost has cut local numbers by as much as 80 percent. The species breeds fast enough to refill those gaps. Bird lice and other common parasites live on the birds. Loss of scrub and hedgerow probably costs the species nest sites. For a bird this small, a long frost is probably more dangerous than any predator.

Population and conservation

The IUCN, BirdLife International and the British Trust for Ornithology all rate the bird Least Concern. It is common through its whole range and thins out only at the edges. Numbers swing hard with the winter weather. High breeding output brings them back within a few seasons. iNaturalist holds 81188 observations of the species.

Most birds move very little in their lives. Ringing in Great Britain gave a median recovery distance of just 2 km. Of adults, 95 percent were found within 20 km of where they were ringed. For birds ringed as juveniles the figure was 60 km. The white-headed northern race is the exception, and it moves far in a hard winter. BirdLife International reports no current threat to the bird.

Relationship with humans

The long-tailed tit does people no harm at all. No farmer or gardener has any cause to object to it. It has moved into gardens and parks in growing numbers. Garden feeders now hold flocks through the autumn and winter. Birdwatchers value the bird for its acrobatics on a thin twig. A hedge left uncut probably gives a pair the thorny cover it needs.

The species has become a standard subject in the study of animal helping. Long-running work on marked birds showed who helps whom, and why. Hamilton's rule predicts that helping pays when the helper and the helped are close kin. A review in 2014 found that the rule holds across many birds, mammals and insects. This tit is probably the clearest bird example of that idea.

In culture and myth

The bird's names probably carry most of its cultural weight. Francis Willughby set down the long tail'd titmouse in 1676. English country speech later called it the bum-towel. That name probably compares the tail to a cloth hanging behind the bird. Animal Diversity Web also records European tit and alpine tit.

Ancient Greek writing gave the genus its name through Aristotle. He used aegithalos for a set of small European tits. Everyday British usage still groups this bird with the tits. It belongs to a separate family, so the common name is likely a historical accident. The nest probably makes the species a favourite in nature writing about craft. The nickname sits alongside long-tailed bushtit in modern usage.