Wanstead Birding

 

 

Lesser Whitethroat - a visitor from the East?

Picture by Tony Brown

The focus for patch birding on Sunday (25^th) was to re-find the previous day’s Corn Bunting, but just after 8am plans changed. I started my typical route of Alex Pond at first light followed by a quick walk up the Ditch of Despair and into the area known as Brooms. This is where a Corn Bunting had been photographed the previous day but overlooked until the days images had done the rounds on WhatsApp and Facebook. The weather wasn’t great with plenty of drizzle and occasional heavier showers, but a few of the local patch birders had commenced bunting hunting. I’d checked all the Broom patches and was moving between the various shrubs that might provide a suitable perch for a bunting. There were several movements from the centre of one small hawthorn bush so I spent a bit of time trying to locate the culprits. After a few minutes a Wren flew out to the adjacent Brooms, and then a Blue Tit, but nothing emerged from one particular spot where there had been some movement. I don’t know why, but I waited, and waited and then got a very brief view of what I was pretty sure was a Lesser Whitethroat head – just the grey head, the white throat, fine bill and typical jizz of a small warbler. Given the time of year my immediate thoughts turned to an ‘Eastern.’ It didn’t fly off but retreated back into the centre of the bush. Bob and a few others were nearby and I went to let them know that I was pretty sure there was a Lesser Whitethroat in the bush – In unison Bob and Jono asked “was it an Eastern?” News spread fast and James sent a message via the Whats App group that this is our latest Lesser Whitethroat record by 22 days.

So, back to the bush. The bird was still playing hard to get, presumably in part due to the light drizzle, but as a sunny spell broke, the bird popped out into a partial, and then full view. It was a Lesser Whitethroat - credibility still intact! The back was clearly light/sandy brown in colour on the back and this did appear to stretch right up to the nape. There did appear to be some subtle buff coloration in the flanks. I got a very brief view of the tail feathers and whilst I couldn’t be certain there was definitely a hint of white – the question was how much? Jono and Bob managed to get some photos but none that conclusively showed the extent of white in the tail – extensive white in the outer feathers is a feature of an Eastern bird - blythi (Siberian Lesser Whitethroat) being the most likely of the races to occur, although halimodendri (Central Asian Lesser Whitethroat) can’t be ruled out (there are 8 records for Britain all confirmed by genetic analysis*). Scrutinising the initial photos the extent and tone of the brown coloration on the upperparts were looking good for our bird to be a visitor from the East – this wasn’t a lingering breeder that had gone undetected for a few weeks.

Below: some of the first good images by Jono that we were able to view in the field that suggested an Eastern bird (Jonathan Lethbridge).

Our bird then flew out the back of the hawthorn bush for a distance of about 20 metres into an adjacent patch of young broom and scattered bramble. Unfortunately, we still hadn’t got a good view of those tail feathers. I’d spent quite a bit of time looking at different Lesser Whitethroat races when I lived in Saudi Arabia – at least 3 races probably occur there, and I knew that the outer tail feathers was a key feature for us to nail. I think I mentioned this more than once to those armed with cameras! After a few minutes in the brooms/bramble the bird made the short flight back into its favoured bush and that was the moment I got good views of the tail – the outer feather on each side of the tail was pretty much wholly white. We were increasingly confident (bordering on certain!) this was an Eastern bird. We spent more time looking at the bird moving through its favoured bush where we watched it defecate – bingo – our first attempt to locate the prize package was unsuccessful. Time wasn’t on my side as I had to leave, but Jono managed to locate a rather poor specimen some time later, followed by the location of the mother of all poos!

Below: contrasting samples

As the morning progressed increasingly good views were had of the bird as it moved between its favoured hawthorn bush and the adjacent patch of Brooms. Eventually several photos clearly showed the outer tail feathers to be primarily white which does, on morphology at least, indicate that our Lesser Whitethroat is a strong candidate for a visitor from the East. As well as making regular flights to the patches of Broom, presumably to feed, the bird was seen feeding several times on the ground below its favoured Hawthorn bush. Apparently this is behaviour more typical of Eastern race birds, although I can’t see much mention of this in the literature. The bird was pretty much silent on the Sunday, although Dominic Mitchell heard a soft ‘tuc’ call on Monday.

A very quick scan of the London and Essex Bird reports suggests that Eastern birds certainly aren’t common in either areas, with the last confirmed record (by genetic analysis) from Richmond in 2018. Most of the regulars managed to get good views of the bird throughout the day and the consensus remains that this is one of the Eastern races, most likely blythi. Of course, time will tell, as the poo samples are now en route to Martin Collinson’s team at the University of Aberdeen.

Extent of light brown coloration to the upperparts and extending into the nape clearly visible. White on the outer tail feathers tantalisingly visible (Jonathan Lethbridge).

 

 Write up by Rob Sheldon