Wetlands

Which, Warbler, Where?!

posted in: Acer Ecology | 0

Ever struggled to tell the difference between a reed warbler and a willow warbler?

For beginner birders the ‘old world’ warblers are notoriously difficult to tell apart at first sight. As a large group of small, often drab looking birds, there is no wonder that they can cause confusion for even keen wildlife enthusiasts. In fact, there are almost 400 species of warbler, formerly grouped into the family Sylvidae. In the UK, they can be broadly subdivided into four groups including resident and summer visitors: leaf (Phylloscopus), reed (Acrocephalus), locustella and sylvia warblers.

In the following identification help guide, features of each group and associated species will be addressed, focusing on habitat, structure and plumage, behaviours and calls:


1. Leaf Warblers

They are amongst the small and slender warblers, and are often sighted flitting around foliage of woodland and scrub habitats. Their plumage is largely shades of green and yellow and they often have prominent wing bars and eye stripes that can help distinguish them from other warbler species.

Chiffchaff

Habitat

  • Resident in southern England and Wales.
  • Summer visitor for rest of the UK.
    (excl. northern Wales and Scottish-highlands).
  • One of the first to return from wintering grounds.
  • Open forest, scrub, parks and gardens.

Structure and plumage

  • Olive-brown.
  • ‘Podgy’, round headed and bodied.
  • Dark legs and bill, and short wings.
  • Noticeable eye ring and short supercilium.

Behaviours

  • Distinct downward tail movement when feeding.

Calls

  • Loud and forceful ‘chiff-chaff-chiff-chaff‘.
  • Sings from crown of large trees.

 

Willow Warbler

Habitat

  • Summer visitor (March – September).
  • Generally widespread.

Structure and Plumage

  • Dull greenish appearance and pale under parts and legs.
  • Yellow tinged chest and throat.
  • Strong eye stripe and pale supercilium.
  • Slim form, fine bill and long-winged.

Behaviours

  • Dashing, fly-catcher like flight.
  • Singular tail movement while feeding.

Calls

  • Soft, descending scale of 3-5 second duration.
  • Ends in a flourish.

 

For more tips on how to identify a chiffchaff from a willow warbler, see the British Trust for Ornithology video below:

 

Wood Warbler

Habitat

  • Deciduous forest.
  • Summer visitor in April-August
    (excl. eastern England and Scotland).
  • Least numerous of the leaf warblers.

Structure and Plumage

  • Largest leaf warbler in Europe.
  • Bright yellow upper parts, throat and chest.
  • Longer winged than willow warbler.

Behaviours

  • Forages high in woodland canopy.
  • Performs ‘fluttering’ song-flights during locomotion from branch to branch.

Calls

  • Two distinct songs.
  • Most common; stuttering notes accelerating into a shrilling trill.

 

To see the wood warbler in action, check out the Internet Bird Collection video below:

 


2. Reed and Sedge Warblers

Typically, reed and sedge warblers are seen in wetter habitats including reed beds and swamps. They are mostly brown in colour, with elongated bodies allowing them easy movement through dense vegetation.

 

Sedge Warbler

Habitat

  • Wetland habitats.
  • Summer visitor across the UK (mid-April – mid-October).

Structure and Plumage

  • Small, plumb warbler; similar in size to a great tit.
  • Largely brown with blackish streaks on mantle.
  • Unstreaked gingery rump and cream under parts.
  • Bold, cream coloured eye stripe and blackish cap.

Behaviours

  • Extrovert, active and curious in nature.
  • Most active during dawn and dusk.

Calls

  • Lively song.
  • Often mimics other birds and sings in phrases.
  • Never repeats the same phrase twice.

 

Reed Warbler

Habitat

  • Reed bed and scrub.
  • Summer visitor (April – October) for southern UK.
  • Large populations in East Anglia.

Structure and Plumage

  • Plain, unstreaked warbler.
  • Brown upper-parts, paler under-parts and rusty-coloured rump.

Behaviours

  • Sings within reed bed, reducing likelihood of being seen.

Calls

  • Monotonous ‘churr churr churr, jag jag, chirruc chirruc’.
  • Complex songs with many phrases.

 

For more tips on how to identify a sedge warbler from a reed warbler, see the British Trust for Ornithology video below:

 


3. Locustella Warblers

Generally live in dense vegetation and often heard rather than seen in their natural habitat.

 

Savi’s Warbler

Habitat

  • Reed bed.
  • Summer visitor (late April – August) to south-east England.

Structure and Plumage

  • Unlike the grasshopper warbler it has no streaking.
  • Dark brown tone to plumage, with a whitish throat.
  • Full, rounded tail.

Behaviours

  • Often seen climbing to the top of the reed stem in damp wetland areas.
  • While on the ground, it cocks its tail up high, hopping on large pale feet.
  • Habitually sings with its bill wide open.

Calls

  • Sings in short bursts.
  • Song often proceeded by sequences of ticks.

 

To see a male savi’s warbler in action, check out the Internet Bird Collection video link below:

 

Grasshopper Warbler

Habitat

  • Summer visitor (excl. northern Scotland) from mid-April – September.
  • Marsh, moor and open woodland.

Structure and Plumage

  • Olive-brown with a faint supercilium and softly streaked brown upper-parts.
  • Small headed with a narrow eye ring.
  • Dowdy/scrawny looking
  • Legs noticeably pale pink or orange.

Behaviours

  • Secretive.
  • Tends to creep through dense vegetation and sighted only when flushed under-foot.
  • Habitually sings with bill wide open.
  • Best seen singing from perches during dawn and dusk.

Calls

  • Distinctive call.
  • Can sound like high-pitched insects, spinning wheels and fishing reels.

 

To see the grasshopper warbler in action, check out the video below:

 


4. Sylvia Warblers

Perhaps one of the more regularly seen groups of warbler, generally inhabiting scrub and woodland areas. Overall, they are more colourful and robust, and unlike other warblers, their plumage differs between females and males.

 

Dartford Warbler

Habitat

  • Scrub and dry lowland heath.
  • Resident in southern and eastern England.
  • Amber listed species.

Structure and Plumage

  • Small and long tailed warbler with a red eye ring.
  • Male upper-parts are grey-brown, lower-parts are red with a whitish belly.
  • Legs are yellowish red.
  • Females are browner in colour with a paler buff and eye ring.

Behaviour

  • Described as restlass and elusive.
  • Tends to perch on topmost spray of low bushes, such as gorse, to sing.

Calls

  • Weak song.
  • Scratching warble.
  • Once on the ground, will create a low djar or rattling trtrtutuk.

 

To see the Dartford warbler in action, check out the video below:

 

Cetti’s Warbler

Habitat

  • Reed bed, swamps and dense vegetation close to water bodies.
  • Resident on southern borders of England and Wales.

Structure and Plumage

  • Rich, chestnut brown above with cream-grey lower-parts.
  • Legs pinkish.
  • Stocky with full rounded tail with only ten tail feathers; unusual for British birds.

Behaviours

  • Skulking bird, rarely seen but often heard.
  • Forages in low dense vegetation.

Calls

  • Explosive call ’chik’.
  • Also calls similar to a stuttering wren.

 

To see a male Cetti’s warbler in action, check out the video below:

 

Garden Warbler

Habitat

  • Edges of woodland, scrub and towns.
  • Summer migrant to most parts of the UK (late April – mid-July).

Structure and Plumage

  • Lack of distinguishing features.
  • Uniformly grey-brown and white below.
  • Large, plumb with a stubby bill and dark eyes.

Behaviours

  • Skulks in thick vegetation but will emerge at tree crowns to call.

Calls

  • Jumbled warble containing mellow phrases.
  • Similar to blackcap but deeper and fuller generally.

 

For more tips on how to identify garden warblers and additionally blackcaps, check out the British Trust for Ornithology video below: