Breckland Birder

Breckland Birder
Water Rail at Thompson Water, Norfolk Photo by Paul Newport

Wednesday, 29 May 2013

Lesser Whitethroat

A Breckland species profile.

The Lesser Whitethroat Sylvia curruca is a summer visitor to the UK generally arriving with us around mid-April and departing at the end of September with some remaining as late as mid October.  Here in the UK, the Lesser Whitethroat is at the limit of its range and is absent from Ireland and rare in Scotland.
Here in Breckland, the Lesser Whitethroat is a reasonably common species where it breeds in tall, overgrown, and generally tree-lined hedgerows.  Unlike its conspicuous relative, the Whitethroat Sylvia communis, a species which sings from a high exposed perch and also during a display flight, the Lesser Whitethroat is a much more of an unobtrusive species, preferring to sing from cover, however, with patience, this bird may creep along a small branch or twig to give some rewarding views. 
As a helping guide to those who wish to watch Lesser Whitethroats in Breckland, two reliable sites include Fairstead Lane, Little Cressingham, and Priory Road, Great Cressingham.  Listen for the rattle-like song of this species in the tall, tree-lined hedgerows, stop, and watch, as the bird may appear to show itself to you.

The Lesser Whitethroat is about 1.5 centimeters smaller than the Whitethroat and with practice, observing these two species will soon show the obvious differences between their plumages.  The Lesser Whitethroat is a very attractive Warbler being smaller and more compact that Whitethroat.  The head and ear coverts are grey, although the ear-coverts tend to be darker, this in turn contrasts strongly with the white throat.  Some birds have a white loral stripe, this may extend around the eye to form a white eye-ring.  The mantle is grey-brown and the wings are a uniform darkish brown, this feature is worth considering if the observer has difficulty separating Lesser Whitethroat from Whitethroat which has a rusty panel on the brown wings.  The tail of Lesser Whitethroat has white edges, the underparts are an off-white, and the legs are grey.
Unlike the Whitethroat which has a harsh scratchy song delivered often from a conspicuous perch, the song of the Lesser Whitethroat is generally given from within cover and is delivered in two parts.  The song starts with a quiet warble, generally only heard when close to the bird, this is followed by a highly distinctive rattle which can be heard at range.  My interpretation of the rattle song is “chikka-chikka-chikka-chikka-chikka”, although other observers may have their own way of interpreting the song as does the text in some field guides.

The breeding habitat of the Lesser Whitethroat differs from Whitethroat in being more arboreal in nature.  This species prefers tall overgrown hedgerows with mature trees whereas the Whitethroat has a preference for scrubby habitats and hedgerows.  The nest is a fine construction of twigs, grasses, hair, and plant down, and is usually quite low down in a dense bush or shrub.  4 to 6 young are raised by both parents and the young are able to leave the nest as soon as they are able to flutter.  

I often say that the Lesser Whitethroat is my favourite Warbler species, but then again, I generally say that about whichever species I am watching or studying at that time.  Maybe it is because this Warbler is at the extreme of its north-west range in Europe, or perhaps it is the migration behaviour of the species, or is it because I marvel at what these delicate birds endure, as do other species, in order to visit us to breed.  Whatever the reason, I never tire of watching these birds and the first arrivals in spring always brings a smile to my face.
Lesser Whitethroat arrivals in spring generally goes unseen as this occurs during the hours of darkness, however, autumn migration can be fascinating to watch as passage birds in good numbers can occur in the right habitats.
 
Knowing where to expect birds, being aware of their behaviour and food requirements, means that it is possible to predict where to find migrants, especially so in autumn.
Within the Breckland area, one of my favourite birding localities in autumn is at Houghton-on-the-Hill, this locality has an elevated position and it is possible to enjoy spectacular visible migration here, additionally, the habitat is such that a number of species occur in good numbers to rest and feed whilst on passage.

         Lesser Whitethroat at Houghton-on-the-Hill August '12 (Paul Newport)
 
During the summer months, Warbler species diet consists of insects, however, during autumn, their diet, including that of Lesser Whitethroat, turns to berries, this diet increases weight and energy levels in readiness for their long journey back to their wintering grounds in Africa.  I find that Elderberries are a favoured food source, therefore, knowing where a good supply of these fruits exists helps with observing these and other migrants.

Migration
Bird passage and migration has always fascinated me and I always marvel at how a creature weighing no more than a few grams, is able to undertake a passage of thousands of miles, encountering man-made and natural obstacles, and breed with us which in itself is fraught with danger.
Lesser Whitethroats winter in North East Africa (Ethiopia, Chad, and Sudan), their passage into Europe takes a very defined route in that they travel from North East Africa, around the eastern Mediterranean, either following coastal routes or taking the small hop from North Africa into Cyprus, crossing over to Turkey, and then north-west through Europe before arriving with us in mid-April.  This route is so precise that this species does not occur in south west Europe (Iberian Peninsula or Italy).  Whilst holidaying in Egypt along the River Nile valley in March 2005, I remember watching Lesser Whitethroats in shrubs and gardens during the early stages of their migration, as they made their way north along the valley from their wintering grounds.  It seems almost incomprehensible that a journey which takes us 4 ½ hours in an aircraft is similarly undertaken by this delicate Warbler over a matter of weeks.   
During September and occasionally through to mid-October, Lesser Whitethroats begin their migration out of the UK, their route is the reverse of the spring passage in that they follow a south-east heading to the eastern Mediterranean and into north-east Africa.  Once again, the Iberian Peninsula and Italy are avoided during this passage.

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