10th December - Hill Head, Hampshire - Siberian Lesser Whitethroat?

 On Friday 9th December Mark Francis reported a Lesser Whitethroat in bushes around the chalets at Hill Head.  He found it in the afternoon and managed to get some photographs but with declining light the images were not the best, what was evident was that this was a Lesser Whitethroat and given the time of year was probably not of the nominate race Sylvia Curruca Curruca.

The following morning Ian and I joined Mark at the same sight to look if the whitethroat was still present, we stayed for about 30 minutes without any sighting but Mark remained and at 12:30 the bird was reported again.  We arrived at the site at 13:45 and the Lesser Whitethroat was showing very well, moving between the bushes and a palm tree on either side of the entrance to the chalets.

The consensus at that time was that this was an "Eastern" Lesser Whitethroat, possibly of the sub-species S c Blythi.  The bird was showing well and I was bale to get some good photographs in good light.

The bird was not behaving like any Lesser Whitethroat I have seen, this could be down to the weather and the need to search for food but it also appeared larger, long probably rather than larger overall.  The upper parts were brown fading into a greyish brown nape and then grey crown.

The bill appeared to be larger and prominent, while the underparts had a buff wash on the sides and a whiter appearance underneath.

The grey of the crown became lighter as it came down around the eye and contrasted well with a very white throat.

In this view you can see that the outer tail feathers are white, with white fringes on the next feather moving inwards.

The taxonomy of the Lesser Whitethroat group is famously complex, with up to a dozen forms proposed. However some ornithologists rationalise these into five forms:-

Curruca (‘Northern Lesser Whitethroat’) of northern Europe and northern Asia. The form blythi found east of the Yenisei (‘Siberian Lesser Whitethroat’) is not recognised as a valid taxon.
Halimodendri (‘Central Asian Lesser Whitethroat’ or ‘Steppe Lesser Whitethroat’) of the steppes of Central Asia
Minula (‘Desert Lesser Whitethroat’) of the Central Asian deserts
Margelanica (‘Margelanic Lesser Whitethroat’) of western China
Althaea (‘Mountain Lesser Whitethroat’) of the Central Asian mountains

Some for example, recognise blythi, whilst the likes of Svensson et al (1992) also recognise the form but include within it halimodendri.

Others however, identify three species groupings based on the existence of three separate song types. These are ‘Northern Lesser Whitethroat’ (incorporating curruca, blythi and halimodendri), the ‘Desert Lesser Whitethroat’ (incorporating minula and margelanica) and ‘Hume’s Lesser Whitethroat’ (althaea).

Confused, it is quite a mind field and difficult to determine what we had here in Hampshire.  Mean while the bird itself had taken a liking to the berries on the Palm.

The nominate race Curruca shows a long wing-point, distinct grey hues in the upperparts and (in juveniles) dusky washes on the outermost tail feather and a dark patch along the shaft, whereas Blythi the assumed sub-species seen here shows a very slightly shorter wing-point, whiter underparts, browner or more gingery hues in the upperparts and a tendency to more white in the outermost tail feather.

The upper parts are clearly a browner hue rather than grey and the wing projection is short, although there is no direct comparison.  From previous photographs we know the outer tail feathers are white.

With a breeding and wintering range at least in part similar to Siberian Chiffchaff, maybe there is a good chance that that the Blythi arrive here in similar numbers to the Sibe Chiffchaff, however as with, ‘Siberian Chiffchaff’, the precise documentation of plumage hues is vital to identification. A claim of an ‘Eastern Lesser Whitethroat’ should therefore demonstrate that the bird was observed well over a considerable period of time in a variety of lighting conditions so that an accurate assessment of plumage hues could be made. All efforts should be made to describe these hues as precisely as possible. Above all, every attempt should be made to photograph the bird and, ideally, take sound recordings. Trapped birds should be extensively photographed and have full biometric details taken. The removal of a feather for DNA and/or stable isotope analysis would also be invaluable.

But whatever species this Lesser Whitethroat is, it was an opportunity to photograph a species that usually remains behind cover, only showing briefly

Here the ginger brown back fading into he crown showing very well.

Here the darker grey behind the eye, with maybe a slight lighter patch or supercillium

The bird has remained and as yet there is still no definitive identification and probably will not be without DNA analysis.  I am happy to say though that this is not a straight forward Lesser Whitethroat, but of which sub species I will leave to those who are far greater experts than I am.