The rarest British white is almost extinct in my home area of Oxon, Bucks and Berks, but thrives in a number of woodlands in Northamptonshire. One of these, Wicken Woods straddles the border with Bucks but my location of choice is Bucknell Wood (SP660451) just outside of Silverstone off the A43. This is possibly out of laziness, having visited before in each season from 2011 to 2013, as the species is easy to find here and I know exactly where to look.

The road to this Forestry Commission woodland from Silverstone is currently closed, necessitating a diversion back onto the A43 towards Towcester, then left at the next roundabout following signs to Abthorpe. On my arrival today a first Wood White ghosted by in the car park. I then walked the main track westward as it was bathed in sunshine (below).

I quickly began to see Wood Whites here and counted about 20 as far as the crossroads in the centre of the wood. These languid waifs have a dainty appearance and delicate flight that easily distinguishes them from Green-veined or Small White, and they are also smaller than those other species. As I fired off the frames from which to select the pictures below, all the frustration of a four day wait for sunny weather melted out of me.

Wood White is localised in southern England and rarely numerous where it does occur. The black wing tips of the males seemed more noticeable today than on my previous visits to this site. These are very apparent in this picture of a courting pair (below).

Having gained such a good result along just part of the route I usually walk here, and mindful of the need to return to Otmoor, I decided against going further into the woods. If anything there seemed to be more butterflies on the wing as I walked back to the car park.

Dainty, delicate, languid and ghostly

When my plans for this morning fell through I was pleased to get an Oxonbirders’ text alert saying there was a Black-throated Diver at Farmoor Reservoir. I jumped into the car and went at once, this being a bird I have seen twice before but not in summer plumage. In the event I was the first local twitcher to arrive on site, and patch watchers Dai and Steve walking back along the central causeway told me the bird was diving close to one side of the famed concrete bank.

Rain having begun to fall on my arrival I had left my camera in the car and realised that in choosing to do so I had missed a good photo opportunity. Once company arrived and the bird drifted into the middle of F2 this error of judgement caused a few wry looks and the county bird recorder suggested I use a carrier bag in future. Very apt advice and why didn’t I think of that? We all watched the BTD for a while then Dai (who has a vehicle permit) returned to get the bird onto his dog Billy’s Farmoor list (see here). So he kindly ran me back to the car park where I swapped my scope for my camera (and carrier bag).

Black-throated Diver

Black-throated Diver

Black-throated Diver

On my return the BTD was being watched close to the causeway hide. Once the others had returned to work or wherever they had to be, myself and one other birder who said he shouldn’t be here were left to watch the bird drifting first one way then the other close to the hide. I was then able to experiment with different camera settings and get what with my equipment were reasonable shots (above). At times the bird would stand up in the water and preen, behaviour I have not observed before.

In the past couple of weeks I have also noted with envy various county birders’ pictures of summer plumaged Sanderling at Farmoor. But whenever I dropped in there were none of this species present. Spotting one today on the opposite side of the causeway I added more reasonable results to my Farmoor waders’ gallery. As usual the sludge and detritus of the reservoir shoreline provided a subtle background to the subtler and delicate tones of this beautiful passage migrant.

Sanderling

I think I am right in saying the reaction of everyone who saw the BTD today was “cracking bird!” I can only agree on both species and all this was a most excellent way of passing a wet spring morning. The BTD remained at Farmoor for nine days but observers realised it had picked up an injury and wasn’t well. Sadly this bird was found dead on 23rd May.

When I read that Marsh Fritillary were flying at my site of choice there was only one place to go on this warm and sunny day. In my home area of Oxon, Bucks and Berks there is just one tiny and fragile cluster left. Not too far away in Wiltshire variable concentrations of the species can be found, and Cotley Hill (ST917427) near Warminster must take the title of Marsh Frit grand central. My visits here in 2011 and 2013 yielded large numbers of what is a declining and distinctly localised butterfly nationally, and today was a repeat experience.

From a lay-by at a roundabout on the A36 near Heytesbury, a footpath leads uphill into a long south-west facing slope covered by unimproved grassland. This site supports a rich flora and 29 breeding species of butterfly. Taking the first sheep track left at the foot of the hill I quickly began to see Marsh Fritillary, as on those previous visits. An observer walking back told me there were hundreds on the hillside above and indeed there were. This butterfly has a pleasing habit of sitting up and keeping still for the camera, and one after another did just that as I walked around.

Marsh Fritillary

Marsh Frit can be very variable, the smallest males being a fraction of the size of the largest females. Although the chequered pattern is constant the wing colours can also vary a lot. Underwing shots are more difficult to come by. This newly emerged female (below) was still drying in the sun while already rejecting the attentions of a male suitor.

The supporting cast here was a check list of April and early May key species: Dingy and Grizzled Skipper, Green Hairstreak, Brown Argus, Small Heath and my year’s first Small Blue.

There was still time for a bonus butterfly so I walked up the main path and back to look for Wall Brown, having seen them here previously and at other Wiltshire sites. This species is virtually extinct in my home area. Back at the lay-by a Wilts man gave me directions to another location where he said they fly. About ¾ mile west of Avebury on the A4 is a lay-by on the south side of the road from where a footpath leads uphill through a Beech copse. On the eastern side of this, above some racing gallops is a worked out chalk pit with an exposed chalk bank. And here indeed I encountered this rather splendid Wall Brown (below).

Wall Brown

Britain’s earliest flying Fritillary has suffered serious declines and is restricted to dry, sheltered grassland and woodland clearings throughout its range. Various sites are now managed to fuel a recovery for Pearl-bordered Fritillary, and my location of choice has been Bentley Wood SSSI on the Hants / Wilts border (SU264293). This large mixed woodland near the village of West Tytherly is a nationally recognised lepidopterist’s mecca since 35 different species are recorded regularly including every woodland butterfly resident in central southern England. Hence there are usually plenty of visitors here to help anyone find things.

Pearl-bordered Fritillary on Bluebell

My day’s excursion followed three weeks of mainly overcast and often showery weather. Just as there is nothing more inspiring than a sunny hillside teeming with different butterflies, so it gets very frustrating hanging around in changeable weather conditions waiting for the sun to break through and butterflies to appear. That is the downside of insect watching. Worse is when the observer leaves home in bright sunshine to see cloud sitting over a site on approach, and worst of all is when the grey stuff rolls in just upon arrival.

Today was my second attempt at PBF, having visited at the end of April but not seen any on a day when four were recorded. I needed to go somewhere and after yet another “brightening later” weather forecast decided to risk it. The Pearls favour an area called Cowley’s Copse that is usually referred to in field reports as the “eastern clearing”. To one side of the access track to the public car park I saw the tell tale sight of a group of observers crouched low with their cameras. That was it: I parked immediately in a convenient trackside place and went to join them. They had found a mating pair on an English Bluebell (below), and who should be amongst this group but Oxon’s very own and finest Wayne and Julie Bull.

On my previous visits here in 2011 and 2013 I gained good though grassy top wing pictures of PBF but still needed underwing studies. Now with conditions remaining overcast on my arrival and hence too cool for the butterflies to be lively, they kept still and allowed a point blank approach. PBF is so called because of seven silver “pearls” along the borders of each underwing, which these pictures (below) show. The large black dot is another diagnostic.

Pearl-bordered Fritillary

Once the pair had finished what they were doing and separated, a photographer moved one of them onto a more artistic perch that he had set up. I wouldn’t dream of such tricks myself (toggers!) but have to say I am very pleased with the outcome (below). Mission and a premium collection photograph having been accomplished so quickly and easily, I didn’t feel inclined to trawl the still overcast forest clearing for more species and so took the opportunity to visit other sites through the afternoon.

Pearl-bordered Fritillary

Me, Julie and Wayne

My first stop was the nearby Danebury hill fort (SU323377) for a bit of history, as is my wont. I don’t know whether this has any particular claims to butterfly fame, but being a previously unvisited iron age site in the Wessex area I wanted to give it a once over. Hill top ramparts are often good for butterflies because of the shelter they provide and when the sun cared to show itself so did several common species. It was an impressive location with lots of suitable butterfly habitat, one I thought worth a future visit to see what is there.

Danebury Hill, Hants

Then it was on to Butser Hill (SU713206) on the South Downs near Petersfield, Sussex. Having left my planned second visit here to the late afternoon, the brightening forecast materialised and I was rewarded with perfect butterfly conditions. As on 20th April I concentrated on Rake Bottom, a deep dry valley on the western flank of the highest point on the chalk ridge of the South Downs. Walking in from the top end then down along the valley bottom, I quickly began to see Grizzled Skipper but these all looked well worn compared to that first visit.

Then I began to find Duke of Burgundy that were flying in good numbers. I knew that Butser Hill was a site for this threatened species, but not that Rake Bottom was the spot for them until now. They were present in low scrub all along the valley floor.

Next up came the visit’s target Dingy Skipper. There can be no more appropriately named British butterfly than this nondescript little number. I have only been used to seeing small numbers of the conservation priority species at any site visited but they are locally common on the South Downs. My experience today bore that out. This was the most numerous butterfly present and given the site’s vastness they must occur here in very large numbers.

This species had been frustrating me locally over the previous three weeks, with just one found on the Chilterns escarpment at Linkey Down prior to today. Dingy also sums up my past attempts at photographing the butterfly that always seems to look “smudgy” in captured images. I had not previously achieved a really satisfying picture of one, though these are better than average.

This is a clearly a butterfly site par excellence as well as a spectacularly beautiful location, and all the common downland species must be present in high season.

At last some rare wader action to end the month! For me this has seemed like an uneventful spring bird passage so far, with only the Hampshire Greater Yellowlegs to go after. Then six evenings ago another Nearctic vagrant, only the third of its kind to be seen in Great Britain arrived at Meare Heath on the Somerset Levels. News was put out early on Saturday once the finder (see here) had made sure of his sighting, but I didn’t notice in time and the bird flew off late afternoon.

I will admit to having to read up on Hudsonian Godwit, not recalling the name previously. The species is so called because almost the entire post-breeding population gathers along the south Hudson Bay and James Bay in Canada. This is a spectacular migrant, wintering in Argentina, and trans-Atlantic vagrancy is very uncommon. In RBA’s weekly summary the bird is said to have acquired mythical status over the 32 years since it was last twitchable here.

I arranged to go down on Sunday with Oxonbirder Andy Last but the “Hudwit” was not relocated. The bird stayed away until Wednesday when it returned with a flock of Black-tailed Godwit and remained until dusk. Where it had been in the interval is not known. Today I was just setting out for what would have been a routine sort of day locally when I got a text from Andy saying the Hudwit was back once more. Suddenly my day had a greater sense of purpose and I upped and went.

On arriving at Ashcott Corner between the Avalon Marshes reserves of RSPB Ham Wall and Shapwick Heath I found the welcome sight of bulging car parks and a procession of birders coming and going. The location was just a ¼ mile to the west but there was a large flock of Blackwits and other common waders to pick the visitor out of (pictured above). Fortunately I stood next to a friendly expert who guided me to the correct bird. At this point the Hudwit, a female was sleeping and the most noticeable diagnostic was a dark coloured belly. But when she occasionally shook her head or preened briefly the bi-coloured, slightly upturned bill and distinctive pattern of the upperparts were plain to see.

See here for RBA’s photo gallery of this bird.

Then I saw Oxonbirder Adam Hartley (aka Gnome) walking towards me to greet some friends of his, so I thanked my helpful guide and went to join Adam. Having got my eye in I could now relocate the Hudwit fairly easily unless it became obscured by other birds, and we watched it mostly sleeping for over an hour. All the time birders were coming and going, with up to 300 present at times. Many of these had the air of vastly experienced twitchers: grizzled, tanned characters with big beards, dated spectacles and carrying all manner of optics; all of this reflecting the great rarity of the bird we had come to see. And a good natured ambience prevailed with people exchanging anecdotes of birding derring do from far and wide

Bittern

As if to demonstrate how I only have to step out of Oxfordshire to trip over Bittern, this one (above) did a fly past. A local bird surveyor told us there are now over 40 booming males on the Avalon Marshes, as well as growing numbers of Great White Egret. Marsh Harrier and Hobby also put in frequent appearances to entertain the crowd. All this is testimony to the huge amount of habitat restoration carried out by the RSPB and English Nature since the 1980s when this area was one largely of peat workings.

At just before 3pm all the Godwits went up and circled round. This was the flight view that everyone had been waiting for since the Hudwit revealed its distinctive dark underwing pattern (pictured below). Adam, who was on an errand to IKEA in Bristol, then had to leave and so I departed too. Back at the car park a business suited man in a BMW pulled up next to me and transformed himself quickly into a birder. He said his day had started in Lancaster, where he saw mainland England’s other mega a Pied-billed Grebe. Then after client meetings there and in Wolverhampton he had time to drop in here before heading home to Bedford. Now that’s what I call achieving a work / life balance!

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