Thursday 28 June 2018

Hopping down to Kent 24th June 2018

Moth and myself decided on a day out in Kent as there were not one but two Bonaparte's Gulls currently residing there, one at Crossness in that part of Kent which is now classed as southeast London and the other at Oare Marshes, further into Kent proper. Also, as a bonus I could realise a long term ambition to go and see Heath Fritillarys at Blean Woods which is near Canterbury and not far from Oare Marshes.

As we left Eynsham it was a day of yet more glorious sunshine in what is turning out to be one of the best summers we have had for some time in this fickle climate of ours.

A Bonaparte's Gull would be lifer for Moth as indeed would be the fritillary for both of us and we  decided to start with  the first summer Bonaparte's Gull at Crossness as the other Bonaparte's Gull and Heath Fritillary were much further away in deepest Kent.  The first summer Bonaparte's Gull had only recently been discovered feeding at the not so salubrious surroundings of the sewage outfall at Crossness on the Thames Estuary and which is adjacent to Thamesmead, a sprawling area of mainly social housing built from 1960 onwards on the south bank of the Thames. Moth is originally from this part of Kent and confirmed my suspicions that it was not the most pleasant of areas in which to go birding, but that was where the gull was and so we had no choice but to get on with it.

I had directions and a postcode for the Satnav from RBA (Rare Bird Alert) which said that we could view the gull from the Thames Path at Crossness, so presumably it would be easy to find and then we could move on to enjoy the more pleasant surroundings of Blean Wood and Oare Marshes.

My heart  had begun to sink well before we approached Thamesmead as we drove though an urban landscape that not even the sunshine, illuminating dubious sculptures on a couple of roundabouts could make attractive and, following the satnav's instructions, we found ourselves in a large industrial estate and nowhere near the Thames. According to the postcode on RBA and the satnav we had arrived at our destination and the industrial estate was where we should be but we were nowhere near the river. To save a long and tedious account of how we drove round a warren of depressing streets in Thamesmead, lost and increasingly frustrated, all I will say is that after forty five minutes of achieving nothing, we all but gave up.The frustrating thing was we could see a road leading to the Crossness Water Treatment works below the main road that we were on but we could find no way of accessing the road below. Every road we tried was either a dead end or blocked off. 

It was getting warmer by the minute and time was passing, so reluctantly the decision was made to cut our losses and head for Blean Woods. We set the satnav and followed its instructions, directing us through yet more roadworks and past more closed off roads until hopefully we would be able to leave the depressing environs of Thamesmead. Just as we passed the last of the roadworks and about to leave Thamesmead both of us, independently, noticed a road on the other side of the dual carriageway we were currently on that we had not tried or noticed before.

We went to a roundabout and doubled back to the entrance of this road, unhelpfully concealed by traffic cones and temporary road signs and there, would you believe it, was a small sign pointing to Crossness Water Treatment works and the Thames Path. We had found our supposed destination by accident and it had taken an unnecessary wasted hour. If only the directions could have been more specific or possibly I had taken care to get more details about Crossness before leaving home.

We drove down the road, convinced we would be looking for the gull in no time at all and came to an unwelcoming barrier to the sewage works which told us in no uncertain terms to not go any further. Now what do we do? We were so near and yet still so far. I refused to give up.

Turning the car around I drove back a little way to where we could access what looked like a formal  tarmac path that headed in the direction of the sewage works and presumably the river.

'Let's try this.' We commenced a long walk along the pathway and found a sign pointing to the Thames Path.  By now we were passing under a flyover, admiring the graffitti and assorted parts of vehicles scattered around and about. We followed the path but the signs for the Thames Path vanished and we were lost. We returned to stand under the flyover and an uncertain track, through the grass, led off in the vague direction of the sewage works.We had tried every other path so this was our last option. I was not optimistic but we took it.

It looked decidedly unpromising after a few hundred metres as we passed through a hinterland of thistles and scrubby grassland, scented by a pungent aroma from the sewage works. A Rose ringed Parakeet shrieked at us from a tall tree and a Common Whitethroat flew from the thistles. I was all for turning back, as hot, tired and frustrated I found myself in a not very good place both spiritually and physically. Just on the point of turning I saw a man wheeling a bike and walking towards us.

He was the first person we had seen for thirty minutes and I enquired of him the whereabouts of the Thames Path, now rapidly taking on mythical status with us. He told us to keep walking on the track and eventually we would come to it.  

We did as he instructed and after half a mile, walking up a slight incline and through a gate, there was the Thames Path, a fairly wide boulevard of concrete stretching away in both directions alongside the expanse of the river,flowing just beyond a high wall that guarded it. From here it was obvious we should walk to the right, as that was the direction of the sewage works.

Following the Thames Path which was currently occupied by a few cyclists, joggers and us, we eventually came to a ramp that allowed us to walk upwards and view the river through  a screen consisting of a number of viewing 'portholes' set into the wall. The screen was presumably erected to stop people throwing themselves in after a similar experience to ours. There was not a gull to be seen which was unsurprising as this was obviously not the sewage outfall. Further on there was a long concrete walkway running out into the river, guarded by a fortified and heavily padlocked gate, with a circular structure at the end of it. Could this be the outfall?

There were certainly a fair number of gulls perched on the rails of the walkway. We wandered up to the padlocked entrance and looked out through the fortified fence but all the perched gulls were Black headed Gulls and I was none too certain this was the sewage outfall anyway. I looked further downriver and a few hundred metres in the distance I could see some gulls and a tern flying over what looked like a small inlet which was obscured by rank vegetation growing up and around its banks. 'Let's try there Moth and if that is a no go we might as well concede defeat. 'Let's give it a go'.

We walked along the concrete canyon, our view of the river totally obscured by the huge concrete wall on our left and on our other side was the huge Victorian and now preserved, Crossness Pumping Station, designed by Sir Joseph Bazalgette in 1865 and currently  a tourist attraction. 

The River Thames is behind the concrete wall that Moth
is walking alongside
We got to the inlet and walking up another slight incline came to a small grassed area on our left with a wall no more than four feet high overlooking the river. We looked over the wall and there, just below, were about a hundred squawking Black headed Gulls, ranged in a semi circle around the roiling brown turgid waters of the sewage outflow. There was no mistake this time. We had finally found the sewage outfall!

The view to the other side of the Thames with the gulls in
the foreground
The gulls were having a field day swimming around in the brown disturbed water, picking off morsels of, I shudder to think what, and keeping up a constant raucous commentary of calling. Scattered like confetti, in close company, they kept just shy of the strongest  upswelling current as the water bellowed out into the river from the sewage works. Now all we had to do was find if the Bonaparte's Gull was still here. We were optimistic as it had been reported earlier in the morning.

Moth, never having seen a Bonaparte's Gull had little idea of what to look for but knew the bird in question  was a first summer, so it would not have a black head. Fortunately the majority of Black headed Gulls were adults and still in summer plumage with brown hoods and therefore could be eliminated. I scanned through the assembled gulls, once, twice and then a third time but could not find the Bonaparte's. It was far from easy anyway, as the gulls were constantly active, making sudden dabbing movements, picking at the water, back and fore and sideways as the uprising water brought various 'titbits' to the surface. Nice.

First summer Bonaparte's Gull
Using my phone I found a picture of this particular Bonaparte's Gull on the internet that had been taken a couple of days ago by the finder and showed it to Moth so he would have some idea of what to look for. A few minutes later he informed me he thought he had located it! He directed me to where he thought it was and there indeed was the little beauty. Obvious now, amongst the Black headed Gulls, I wondered how I could have missed it. 

Once we had 'our eye in' so to speak, it was relatively easy to pick it out with the naked eye as its demeanour and subtle structural differences gave it away in the throng of gulls.

The gull was fractionally smaller than the surrounding Black headed Gulls. structurally more delicate and to my mind was a slightly darker grey on its mantle. Its bill was black and its feet and legs flesh pink while its white head was sullied with black smudges. It swam amongst the other gulls, unphased by them and quite feisty, fully prepared to threaten with partially open bill any gull that came too close, and it fed in a similar manner to them, delicately picking morsels off the turgid water. 

The Bonaparte's Gull with Black headed Gulls
Its feeding action was faster  than the other gulls and vaguely reminiscent of a phalarope, as it made quick darts and stabbing movements to either side and in front whilst rapidly paddling. It came close  on a number of occasions and then drifted away to the outer peripheries of the flock, when it would  fly back into the main congregation of gulls and the whole process would be repeated ad infinitum. Its wings, when it flew showed the diagnostic pure white undersides on the outer primaries and in flight I could see it had already commenced its wing moult on the inner primaries.

Bonaparte's Gull and adult Black headed Gull
Bonaparte's Gull in flight with swimming Black headed Gulls. Note the
strange shape of the outer wings due to the wing moult on the inner primaries

What a smashing little bird and we savoured the reward of the righteous after our marathon logistical effort to get to see it. A couple of recently fledged Black headed Gulls, still in their mixture of pale ginger brown, grey and  white plumage were amongst the flock but already beginning to moult into the standard grey and white plumage of a first winter bird.

Adult and juvenile Black headed Gulls

A small flock of Common Terns fed with the gulls but unlike the gulls that swam on the water, the terns remained in the air, circling overhead above the most turbulent part of the outflow, diving down with sharp cries to seize a food item, hitting the water with a resounding splash. At first there were only three Common Terns but slowly the number rose to around fifteen. Similarly the gull numbers also rose while we watched.

Common Terns
We lost sight of the Bonaparte's and then re-found it. We took its photo and generally indulged in a bout of self congratulation for about forty minutes, having the gull close to us and giving exceptional views, before we were joined by two other birders. 

'Is it showing? they enquired. 

'We have brought some bread.'  

'You won't be needing that' I replied. 

Pointing, I said, 'It's over there at the back of the flock  but it will fly in closer if you wait'.

It did just as I said and we left as it was now lunchtime and we had another ninety minute car journey to the RSPB's Reserve of Blean Wood.

We walked back across the waste ground with me wondering if the car would have all its wheels still intact, as the place where we had left it looked none too secure. I need not have worried as it was all in one piece and with relief both of us headed out of Thamesmead and towards a more rural and enticing part of Kent.

After a slight hiatus we found the RSPB's entrance to Blean Wood. I was unsure what to expect and certainly did not know where to look. In the end we opted for just following a track and trusting to luck. Heath Fritillarys are very rare, due in the most part to loss of habitat. It has very special requirements that are based on regular coppicing of its habitat, something that has died out with modern forestry practices. It requires rotational clearing of the ground so there is a succession of suitable habitat that encourages its foodplant, Common  Cow-wheat, to grow and where the butterfly can move, once its current habitat becomes unsuitable. 

Heath Fritillary habitat
These cleared areas were fairly obvious on the reserve but we could not find any sign of a fritillary but only the occasional Meadow Brown or Ringlet. Undaunted we carried on searching the cleared areas where they were in sunlight. After about half an hour Moth spotted a small ginger coloured butterfly with darker chequering on its wings, flying very low above the track we were currently standing on. The butterfly settled briefly on a bramble flower and there was a Heath Fritillary, a first for both of us.

Heath Fritillary
It was smaller than I expected but nevertheless I was very pleased to see it. We stopped here and over a period of forty five minutes we saw a small number, probably no more than ten Heath Fritillarys, coming and going from what was obviously a favoured area. Most were males flying endlessly, looking for the females that hide in the low vegetation but the males too would settle briefly to nectar from bramble flowers and this was our opportunity to get some photos.You had to be quick as they did not settle for long before flying off, always low to the ground searching for females.The ultimate prize in any fritillary photo is to get an image of the underside of their wings, as this is where the beautiful marbling of irregular white markings can be seen.

Having got our photos we wandered the various trails and found a little further on a White Admiral cruising in its distinctive gliding flight through the surrounding trees and eventually it too settled on some bramble to suck up the nectar from the flowers and Moth got yet another lifer. Such beautiful and elusive insects, they, in my opinion, have the most lovely patterning on their underwings of any of our native butterflies.

White Admiral
The White Admiral eventually flew off, powering away with a few flicks on  flat wings and we walked on but saw little else apart from a couple of Painted Lady butterflies.We went back to the Heath Fritillary 'hotspot' and spent another twenty minutes there with one very tatty male, his wings torn and scuffed and who had not long to live.He returned time and again to some ferns by the track, basking on the green shiny fronds in maybe the last day of his short life.

Energised by our success with the Bonaparte's Gull at Crossness and the Heath Fritillarys at Blean Wood we decided that we would try for the other Bonaparte's Gull, an adult this time, in full summer plumage, at Oare Marshes just half an hour's drive away. Oare Marshes is a seventy acre Local Nature Reserve owned by Kent Wildlife Trust and located on the south bank of the Swale Estuary. It has a feeling of remoteness and calm, almost a step back in time, despite its proximity to the town of Faversham. It has been years since I have visited here but we found it with little problem and parked by an area of open water, reeds and a couple of islands called The East Flood. This is where the gull had been reported from earlier in the day but there was no sign of it now.

Two separate flocks of Black tailed Godwits were roosting here, some still in their barred and rusty orange breeding plumage with a few Avocets among them.

Roosting Black tailed Godwits
One of the flocks was roosting on a small island and, very much obscured in amongst them, was a small grey and white gull with a distinct black rather than brown hood. This had to be the adult Bonaparte's and indeed it was, as eventually it woke up and turning its head, showed off its black bill.

Adult Bonaparte's Gull in amongst the Black tailed Godwits
I would have liked to have seen more of it but shortly afterwards it flew high in the sky and far away, following the Oare Creek and we decided to leave matters there as it had been a long but rewarding day and there was now a three hour drive in prospect to get back to Oxfordshire.


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