Sykes' Warbler is an Old World warbler

Old World warbler

The "Old World Warblers" is the name used to describe a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into...

 in the tree warbler

Tree warbler

Tree warblers are medium-sized warblers belonging to the genus Hippolais, formerly placed in the "Old World warbler" family Sylviidae but now separated in the marsh- and tree-warbler family Acrocephalidae. They are found in Europe, Africa and western Asia....

 family. It was formerly considered a subspecies of the Booted Warbler

Booted Warbler

The Booted Warbler is an Old World warbler in the tree warbler group. It was formerly considered to be conspecific with Sykes' Warbler, but the two are now usually both afforded species status...

, but is now considered a full species. Its breeding range

Range (biology)

In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...

 is from northeast Arabia

Arabian Peninsula

The Arabian Peninsula is a land mass situated north-east of Africa. Also known as Arabia or the Arabian subcontinent, it is the world's largest peninsula and covers 3,237,500 km2...

 to Afghanistan

Afghanistan

Afghanistan , officially the Islamic Republic of Afghanistan, is a landlocked country located in the centre of Asia, forming South Asia, Central Asia and the Middle East. With a population of about 29 million, it has an area of , making it the 42nd most populous and 41st largest nation in the world...

. Like the Booted Warbler, many populations of the species migrate

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 in winter to the India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

n subcontinent as far south as Sri Lanka

Sri Lanka

Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

.
There are differences in the nesting and egg morphology between rama and caligata. It has been suggested that the rama group can be separated from Hippolais and the older genus name of Iduna was proposed and molecular data supporting the Iduna clade was found in 2009.

It is a small passerine

Passerine

A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...

 bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s are found in open country with bushes and other tall vegetation. 3-4 eggs are laid in a nest in a bush or vegetation. Like most warblers they are insectivorous.

It is a small warbler, especially compared to others in their genus. They are pale brown (weak tea colour) above and whitish below with buff flanks. The outer tail feathers have pale edges. They have a short pale supercilium

Supercilium

The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...

, and the bill is strong and pointed. Sykes's is larger and greyer than Booted, and most resembles an Eastern Olivaceous Warbler

Eastern Olivaceous Warbler

The Eastern Olivaceous Warbler is a "warbler", formerly placed in the Old World warblers when these were a paraphyletic wastebin taxon. It is now considered a member of the acrocephaline warbelrs, Acrocephalidae, in the tree warbler genus Hippolais ...

.