The booted warbler (''Iduna caligata'') is a species of

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

bird belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Acrocephalidae, the reed and tree warblers. This species breeds in Eastern Europe and western Asia, wintering in south Asia. it is a regular

vagrant Vagrancy is the condition of wandering homelessness without regular employment or income. Vagrants usually live in poverty and support themselves by travelling while engaging in begging, scavenging, or petty theft. In Western countries, ...

to Western Europe.

Taxonomy

The booted warbler was first formally described as ''Sylvia caligata'' by the German

physician A physician, medical practitioner (British English), medical doctor, or simply doctor is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through the Medical education, study, Med ...

explorer Exploration is the process of exploring, an activity which has some Expectation (epistemic), expectation of Discovery (observation), discovery. Organised exploration is largely a human activity, but exploratory activity is common to most organis ...

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

and

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Martin Hinrich Carl Lichtenstein with its type locality given as the Ilek River, near

Orenburg Orenburg (, ), formerly known as Chkalov (1938–1957), is the administrative center of Orenburg Oblast, Russia. It lies in Eastern Europe, along the banks of the Ural River, being approximately southeast of Moscow. Orenburg is close to the ...

. This species is now classified in the genus '' Iduna'', the tree warblers, within the family Acrocephalidae. All the "Old World warblers" were formerly classified within the wastebin taxon known as

Sylviidae Sylviidae is a family of passerine birds that includes the typical warblers ''Sylvia'', and closely related genus '' Curruca'', formerly included in ''Sylvia''. They are found in Eurasia and Africa, with the greatest diversity in the Mediterrane ...

sensu lato ''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular co ...

'', but in the late 20th Century, molecular studies resulted in this taxon being divided into a number of families. It was formerly considered to be conspecific with Sykes's warbler, but the two are now usually both afforded species status.

Etymology

The booted warbler belongs to the genus ''Iduna'' which was proposed by Alexander Keyserling and Johann Heinrich Blasius in 1840, but they gave no explanation of the genus name, though in

Norse mythology Norse, Nordic, or Scandinavian mythology, is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia as the Nordic folklore of the modern period. The ...

, Iðunn, or Iduna, is the goddess of spring and fertility who was changed into a sparrow (or a nut) to enable her rescue by

Loki Loki is a Æsir, god in Norse mythology. He is the son of Fárbauti (a jötunn) and Laufey (mythology), Laufey (a goddess), and the brother of Helblindi and Býleistr. Loki is married to the goddess Sigyn and they have two sons, Narfi (son of Lo ...

. The specific ''caligata'' is

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

for "booted" from ''caliga'', "boot".

Description

The booted warbler is a small species of warbler, similar in size to a

common chiffchaff The common chiffchaff (''Phylloscopus collybita''), or simply the chiffchaff, is a common and widespread leaf warbler which breeds in open woodlands throughout northern and temperate Europe and the Palearctic. It is a bird migration, migratory ...

. It has an undistinguished plumage which is plain greyish brown on the upperparts and paler on the underparts. There is a clear, pale supercilium and a short bill with a dark tip. The jizz shown is of a short-winged rather pot-bellied warbler with a square-tipped tail. This species and Sykes's warbler are challenging to identify.

Distribution and habitat

The booted warbler itself breeds from central

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

to western

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, and migrates to winter in the

Indian subcontinent The Indian subcontinent is a physiographic region of Asia below the Himalayas which projects into the Indian Ocean between the Bay of Bengal to the east and the Arabian Sea to the west. It is now divided between Bangladesh, India, and Pakista ...

as far south as

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

. Booted warbler has expanded its breeding range westward in recent decades and nests now as far west and north as

Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...

. This species is a regular vagrant to Western Europe with, for example, over 180 records in Great Britain up to 2023.

Biology

The booted warbler nests between May and early July, building a nest which is shaped like a cup and created from twigs, roots, stems and leaves, lined with feathers, animal hair and plant down. The nest is located on or close to the ground, or at a maximum height of 1 metre above the ground, hidden among dense undergrowth. It is mainly insectivorous.

Gallery

File:Booted Warbler, Iduna caligata.jpg, Booted warbler seen in

Udumalpet Udumalaipettai also known as Udumalai, is a town in Tiruppur district in the States and union territories of India, Indian state of Tamil Nadu. It is located 535 km (332 mi) south west from the state capital, Chennai and 72 km (45 ...

Tamil Nadu Tamil Nadu (; , TN) is the southernmost States and union territories of India, state of India. The List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of Indi ...

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

File:Iduna caligata MHNT ZOO 2010 11 201 Pérowsk.jpg, Eggs of ''Iduna caligata'' MHNT File:Booted warbler (Iduna caligata).jpg, Booted warbler (''Iduna caligata''), Palakkad, Kerala, India

References

booted warbler Birds of Russia booted warbler {{Acrocephalidae-stub