Sunday 29 April 2018

A Spring day at Farmoor 26th April 2018

It was back to Farmoor Reservoir today to wander at will, with no particular purpose in mind other than to just generally birdwatch and put my birding fate in the hands of chance.

The surrounding countryside is now rapidly transforming into infinite and subtle varieties of bright green as the fast emerging vegetation eradicates the dull tapestry of winter. The increasing pulse of regeneration brings a sense of urgency to my consciousness as I look around at a landscape that is changing before my eyes into one of bounteous profusion and a richness of life and colour. Ground that has been bereft of plant life throughout winter is now made attractive, simply by the annual cycle that brings another generation to life.

Cowslips, one of the most loved of our  native perennial wild flowers, form dense clusters of nodding yellow heads above the growing grass on neglected verges, their pale stiff stalks holding erect the  deep yellow flowers, each small trumpet shaped flower crowning the end of a pale green and bulbous calyx. If flowers can ever be called sociable then cowslips qualify as they never grow alone but form clusters of plants, growing close to each other and spreading out in a riotous profusion of yellow, like scrambled eggs strewn across the grass.

The western bank of Farmoor's smaller reservoir is especially favoured with them, growing in great swathes but I found a man mowing them to oblivion and on asking why was told that the banks had to be mowed because that is what the reservoir engineer, who had contracted his company to do so, had instructed. After some discussion I spoke to the man's manager on the phone and he agreed that the cowslips could be spared after all and he would advise the reservoir manager. A small victory for common  sense.

Celandines, another messenger of Spring, strike their slimy roots and grow in the damper, shaded  places, forming patches of dark, heart shaped, green leaves  below short stems that support star like flowers of a metallic shining yellow. The brown and bare corridors below hedge bottoms are being concealed by burgeoning plant life. Cow Parsley, Garlic Mustard and Nettles fill the void of winter and creep up through and over the bare twigs and stems at the base of the hedges, where they love  to grow and thrive.

A welcome harbinger of early Spring days, a male Orange Tip butterfly, flies fast and low, stopping its flight for brief moments to touch down on a leaf, before fluttering ever onwards on its quest for a female, the orange wing tips flickering bright like flame in the sun, as it fusses along the hedgeline

Many trees are coming into leaf, some more so than others but the latent promise is there, even on those still partially bare, as their bulging buds of leaf will burst and spread any day now. Blackthorn confounds its name, concealing the dense dark tangle of twigs and branches by clothing itself in a froth of  delicate white flowers. Always the first to flower, each bush forms a large and irregular white patch in the otherwise plain green hedgerows of hawthorn that run between the reservoir and the nearby River Thames. 

As I ventured up the bank to the reservoir's perimeter track it was sunny and bright but a strong and bitter southwesterly wind battered at my windproof jacket. Looking down from the track I found a Mallard and her brood, tucked cosily out of the wind in a little cul de sac of concrete by the sheltered water below me.The ducklings formed a living pillow of soft brown and buff down as they snuggled into each other, using a pad of windblown discarded gull feathers to rest on, whilst their mother, a few feet away, kept a benign eye on me.

Further along, where the wind was lashing the waves into a froth against the concrete wave wall, Black headed Gulls were in a frenzy of feeding on whatever was being brought in by the wind blown water. Overhead a dozen or more Swifts arrived from the East, riding the wind on crossbow wings, tilting their stiffly held wings from side to side, tacking like the yachts that ply the reservoir on weekends, as they subjugated the wind to their will. Alternately gliding or on rapidly flickering wings they made their way into the teeth of the wind, high above the reservoir, black silhouettes now, against patches of troubled blue and grey sky.

Only one male Yellow Wagtail was braving their favourite grass bank by the Thames Waterworks, feeding half way down the slope to be out of the wind that was roaring up and over the reservoir wall. As ever it stood out on the green grass, a tiny sliver of olive and brightest yellow.

Yellow Wagtail
As I turned up the central Causeway the wind caught at my windproof coat and set it rustling and vibrating, flattening it against my body. Careering over the open waters of the larger of the two reservoirs there was little to hinder the wind's force and it was far from pleasurable walking into it. Slowly, as I progressed, the pressure of the wind diminished as I passed the epicentre of its direction and force.

Quieter and in a slightly calmer environment now, I noticed, after my eyes stopped watering, how the water levels have fallen on the reservoir, exposing an area of sandy concrete along which a few Pied Wagtails were running by the churning waters. They were reluctant to turn and face me, for if they did their long tails were instantly blown up and over their backs as the strong wind caught at them. Instead, with a bright loud call, they flew back and around me, carried at high speed by the wind to settle once again on the wave wall.

Almost at the end of the causeway I came across four Dunlin, diminutive and as is usual with this species, hardly troubled by my close proximity. To them I must appear huge and potentially threatening as they peer up at me standing ten or more feet above them on the causeway. That they do not flee always amazes me as I must surely seem an intimidating presence. On rapidly moving black legs they scuttle along the water's edge, stopping every so often to regard me and re-assure themselves there is no real need to fly. They feed at speed, picking tiny morsels endlessly from the watery edge to refuel so they can complete their marathon journey northwards.

They are all in their breeding plumage, having moulted and made a remarkable transformation from the drab and grey plumage of winter into an attractive and complex patterning of rufous turtle shell patterned upperparts, and undersides  of white encompassing a prominent gash of black on their belly. They do not like me stopping to photo them and run hastily away but will not take the last resort of flying.

Maybe they are tired. Maybe they do not want to expend valuable energy for such little purpose. I leave them and walk on, only to come to another small wader whose breeding dress is drab, being earth brown above and white below. It is a Common Sandpiper.

The sandpiper's plumage may be of little consequence but it has journeyed thousands of miles from southern Africa, crossing oceans, deserts and huge conurbations to rest here for a day or so before moving to breed either further north in Britain or beyond. Of all the waders that land at Farmoor they are by far the  most wary, hardly ever allowing you to come remotely close to them, before they are away on flickering  bowed wings, flying low over the water, to settle on the far side of the reservoir. As if to confound me this individual allowed a marginally closer approach  than normal but was still unreasonably wary.

Common Sandpiper
At the end of the Causeway I stopped to check the owl box high up on the Thames Waterworks pumping house. Originally put up for the Barn Owls it has long since been commandeered by a pair of Kestrels  and here they breed successfully each year. Today it was occupied by the female Kestrel sat in the opening looking out. Doubtless it felt sheltered from the wind by remaining within the box but soon it would need to hunt.

Common Kestrel
A Cuckoo called for quite some time from the huge venerable Willows  by the pumping station. Sometimes they are easy to locate in the trees but at other times they only reveal themselves as they drop out of the tree and fly from cover like a hawk, sleek and grey, showing white tipped tail feathers and barred underparts, to seek out another perch from which to advertise their presence. Just after it ceased calling, another called much more distantly and I could see it through binoculars perched on an outside bare branch, swinging its long tail around as it swayed its body and called, over and over.

I sat for a while on a concrete bench on the reservoir's western side, where it was sheltered by a stand of trees and I could be warmed by the sun. Looking out over the glittering waters of the larger reservoir that lay before me I could see hundreds of Sand Martins crossing and re crossing the sheltered southwestern side of the reservoir. With practice it is possible to tell one hirundine species from another just by their shape and jizz. Sand Martins are small, with relatively short wings and tail and a fluttery, fussy, flying style, often moving around in threes in the flock and uttering a distinctive churring call. There is no confusion with Swallows, whose longer wings and tail impart a more leisurely, elegant flight action. I estimated there were  about five hundred Sand Martins feeding over the reservoir waters with just a few Swallows amongst them. It was quite a sight and I spent more time than I needed watching them but I needed to press on and reluctantly rose from the bench.

My intention now was to find some warblers along the Thames Path that runs alongside and below the western end of the reservoir. It was sheltered from the wind here and almost another world, enclosed as it was by trees and bushes on either side.

Thames Water have created three tiny reserves here, Pinkhill, Shrike Meadow and Buckthorn, which provide scrub and good riparian habitat for warblers and I was not disappointed, especially when I found my first Garden Warbler of the year singing lustily from a hawthorn right by the path. Sedge and Reed Warblers are now occupying the reed beds, the rapid, scratchy and almost hysterical notes of the Sedge Warblers that inhabit the margins of the still dead reed stems contrasting with the more rhythmical but still hardly tuneful efforts of the Reed Warblers that prefer the heart of the reed bed, hiding at the bottom of the dead reeds to sing and await the green blades of this year's new growth on which to construct their nests.

Willow Warblers  floated their sweet, wistful refrain, a tiny waterfall of notes, from the thin willow fronds hanging over the path and a Blackcap's rich and note pure warble added to the varied and ever present chorus of warbler song. Finally a Cetti's Warbler announced its hidden presence by volleying an energetic and short crescendo of loud notes  from a sheltered bramble.

I stood quietly under a tree and watched two Blackcaps, a pair, moving about on the edge of a nearby hawthorn hedge.The male, grey all over with a soot black cap was reluctant to come out from the cover of leaves and the secure  confines of a tangle of twigs but the female was less so, her more olive toned plumage duller than the male and with a ginger brown crown. They soon slipped away into the re-assuring cover of the hawthorn. It is early yet for Blackcaps to be breeding but they will soon have a nest in a small elder or bramble.

A male Blackbird perched on a nearby gate post and commenced gently singing, his eye ringed with gold and his yellow bill hardly opening.

For those old enough to recall, surely they are the John le Mesurier of bird songsters. The languid, soothing notes, mellow in cadence and delivered at an unhurried pace as if nothing on this earth was troubling or worth getting anxious about.

Would that it were so.

Monday 23 April 2018

Different from the Others 23rd April 2018

Personally, one of the joys of Spring in Oxfordshire and which I always eagerly look forward to is the arrival of migrant Yellow Wagtails at Farmoor Reservoir.

Invariably the first to arrive are the males, all bright and shining buttercup yellow on heads and underparts with  greenish upperparts suffused with yellow, then add a natty black tail, bill and legs and they are an absolute picture and surely much under rated as one of our most strikingly colourful and vivacious native birds.

They are usually to be found by the edge of the tarmac perimeter track running above the grass bank that slopes down to the waterworks. Here there is a myriad of hatching flies and other insects to be gleaned from the track and bank, and they will often stand in the short green grass, still and uncertain  as I approach, their bright yellow heads and breasts all that is visible, confusing amongst the similarly yellow dandelion heads and swathes of purple blue ground ivy.

The Channel Wagtail with two Yellow Wagtails

Their numbers are declining but still, every year, double figures can be encountered, the birds scattered in a loose knit group along the perimeter track which they often share with Pied Wagtails and the occasional migrant White Wagtail. Sometimes they will fly a short distance to wander the concrete edges by the waters of the adjacent Farmoor One reservoir or fly with a cheery high pitched call to sit on the buildings and disused filter beds of the waterworks.

Male Yellow Wagtails
The majority are migrants passing through, stopping to take advantage of the abundance of flies to replenish energy reserves after their journey from winter homes in West Africa and before moving onwards to their breeding areas. April is always the peak month to see them at Farmoor and by mid May they are hard to find. I think the same individuals are not present throughout but that a continued passage of individual birds passes through over the period. Later the duller females are also often to be found joining the males.

For the last three years at least, the Yellow Wagtails have been joined by a rather beautiful hybrid male wagtail. This hybrid goes under the unofficial name of Channel Wagtail. Its parentage is the result of a pairing between Britain's subspecies of Yellow Wagtail Motacilla flava flavissima and a Blue Headed Wagtail Motacilla flava flava  which is to be found breeding as close as France and throughout western mainland Europe and western Russia. Both are considered to be a sub species of Yellow Wagtail and are part of a wider complex of sub species all encompassed under the catchall of one species, the Yellow Wagtail Motacilla flava.

Male 'Channel' Wagtail
Such hybrids can often catch out the unwary as they are not dissimilar to a true Blue Headed Wagtail but hybrid males at least can be told by the subtly paler colouration of the head and the fact that the yellow of the chin is replaced by white.

Let's forget the taxonomy for now and just enjoy the fortuitous combination that has brought about this lovely looking bird. It retains the bright yellow underparts and yellowish green upperparts of the normal Yellow Wagtail but its head, depending on the light is an exquisite shade of pale powder blue or grey with a prominent white supercilium, markedly different to the bright yellow heads of the Yellow Wagtails.

Channel Wagtails whilst scarce, are usually reported annually from Britain, involving one or two individuals from scattered locations. That one should have graced Farmoor for at least the last three years is remarkable and it could well be that a male, in a previous year, that was seen throughout the Spring and summer, formed a pair with a female Yellow Wagtail and bred nearby, so possibly the male here this year could be one of the progeny rather than the original male.

On any visit to Farmoor I always make a  point of seeking  out the Channel Wagtail amongst the Yellow Wagtails as it wanders through the grass seeking flies. Sometimes it is there and at other times I am disappointed, but that only leaves me with an increased desire to see it the next time.

Tuesday 17 April 2018

Hitting the Heights at Hinksey 16th April 2018

I was just setting off for Farmoor when a text alert arrived from Ian, our esteemed County Bird Recorder and was quickly followed by one from Badger. Both conveyed the startling news that there was a singing Iberian Chiffchaff at Hinksey Heights Golf Course which lies just southwest of Oxford and adjacent to the A34.

This was a 'drop everything and get there as fast as possible' alert as far as I was concerned for I had yet to see one in Oxfordshire, where it is a very rare bird indeed, the last one being seen in 2000 at Great Tew, which I missed. A county mega without a doubt and a national rarity to boot.

The Iberian Chiffchaff had been found yesterday afternoon by Justin, who, whilst waiting to collect his son from a party at the golf club, wandered around the scrubby area running down to the nearby A34, below the golf club car park, and heard an unfamiliar song coming from the trees. He recorded the song and sent it to Ian, suggesting it might be an Iberian Chiffchaff. At first Ian was unsure but then in the evening decided it was the genuine article, informed Justin and the  news went out the next morning.

I got to the golf club, a forty minute drive for me, sometime after ten thirty in the morning to find only Roger, another Oxonbirder, looking for the bird and standing on a track below a hedgerow of hawthorn that screened the golf club car park from a downward sloping area of rough grassland, scrub and golden studded willow or sallow trees. In the distance, from our elevated position you could even see the fabled dreaming spires of Oxford.

Roger told me the Iberian Chiffchaff had just been singing but there was now no sign as it had flown off a long way and out of sight, to where the ground sloped down to the A34. Apparently it had done this once before this morning and returned  but that was of little comfort in my immediate situation. I would just have to be patient and wait to see if it returned like last time.

Pete and Steve, two more local birders joined us and later so did Jeremy and Mick, as more Oxonbirders made their way here to see this county mega.

We all stood in a group hoping it would somehow materialise but it didn't. I wondered what to do and in the end followed a nature trail that led in the rough direction of where Roger had said it had flown but despite walking quite a long way I could hear or see nothing that remotely resembled the Iberian Chiffchaff and returned to find the others also at a loss, so we continued to wait but there was not a sight or sound of the Iberian Chiffchaff.

It was sheltered, even warm where we were standing out of the brisk cold wind, and the sun warmed me so much that I decided to discard my waterproof jacket back in the car and duly returned the short distance to the car park. Just as I got to the car I heard the distinctive and unmistakeable song of the Iberian Chiffchaff  coming from the other side of the hedge. Surely someone was playing a tape of its song but no, on checking through the hedge I could see the others below me on the track intently looking into a large willow tree. The Iberian Chiffchaff had returned. It was the real thing!

I immediately went from a state of resigned relaxation into one of high anxiety and it took but seconds for me to race round and down to the track to join the others and there was the non descript brown and white, small and unassuming leaf warbler that had brought us all here, belting out its surprisingly loud song, perched amongst the myriad golden dusted, green, thumb like flowers adorning the large willow tree.

Tiny and at times difficult to follow in the tree, it left us in no doubt about its continued presence, for it sang constantly as it moved through the whip thin branches hunting invertebrates and often moving to the very outside of the tree to briefly perch and sing. It was rarely still for more than thirty seconds, constantly on the move looking for prey and only stopping briefly to sing, before once more patrolling the tree for food.

It comprehensively searched each tree before moving to another, moving quite frequently from tree to tree but restricting its wanderings to the sloping area of scrub and trees below us and the smaller slope behind us. It rarely descended below head height and usually maintained a much higher position in whatever tree it favoured.

The differences between an Iberian Chiffchaff and our Common Chiffchaff are extremely subtle apart from their songs which are diagnostically different. The Iberian Chiffchaff's greenish brown upperparts and buff white underparts are a tad brighter than a Common Chiffchaff and the sides of the breast and under tail coverts can appear yellower while the supercilium is more prominent and can also show yellow in front of the eye. There was talk amongst us about wing formulas and primary projection but frankly these and the other plumage characteristics mentioned above are virtually impossible to discern or identify in the field with any confidence or authority and most, if not all Iberian Chiffchaffs are unidentifiable in the field unless they sing. That is the one  diagnostic feature that can allow  identification of an Iberian Chiffchaff in the field with any confidence.

Intriguingly we were also a little perturbed to  hear the Iberian Chiffchaff suddenly revert to the song of a Common Chiffchaff but only on a very few occasions and each time it did, it was for less than a minute. A paper published in British Birds explains that this can happen and why it is not a reason for immediately discounting the bird's credentials as being a genuine Iberian Chiffchaff.

Unfortunately the link to the British Birds paper does not work but if you Google 'Iberian Chiffchaff Identification' the relevant article should come up. It is entitled as follows:

'Identification of vagrant Iberian Chiffchaffs - pointers, pitfalls and problem birds' 
by J .Martin Collinson and Tim Melling

I remained looking at the Iberian Chiffchaff for over four hours and it became quite a social occasion as most of the birders coming to see the bird were local Oxonbirders. It was good to meet up with Phil after such a long time and to see him well and enjoying life whilst Mick, a recent arrival from Yorkshire, demonstrated that the traditional way of recording a bird by making field notes and drawings was not entirely redundant. Sometimes with everyone carrying a camera these days we forget how good, satisfying and thorough it is to make notes in the field and record our impressions instantly into notebooks

Hinksey Heights Golf Club could not have been more friendly and co-operative and willingly gave us free run of the area which was so refreshing compared to some experiences with golf clubs around the country that I have encountered. I joined Keith and Shirley in the 19th Hole for a pleasant lunch and then returned for another hour to continue looking at the Iberian Chiffchaff, but it was becoming slightly more elusive now, spending increasingly more of its time in some distant trees and only occasionally approaching as closely as it did in the morning.

It was time to go.

Update 20th April 2018

Sadly it looks like this potential addition to my list of species seen in Oxfordshire is not to be.The song and certain other biometric anomalies have sown an element of doubt about the exact identity of this very confusing bird. It appears to exhibit a mixture of Iberian Chiffchaff and Common Chiffchaff traits and as such is unlikely to be accepted as a bona fide Iberian Chiffchaff by the BBRC (British Birds Rarities Committee). Nevertheless it has been very instructive to study this bird which may never be assigned to either species due to the various anomalies.