One Sedge Warbler in Particular - May 2020

To walk along the Thames Path by the river at this time of year, early on a May morning, is to encounter the natural world at its very best. The rapid acceleration of new growth ushers a bewildering variety of shades of green to clothe the land, fresh leaves transforming the skeletal outline of trees into rounded and softer profiles, the new grass studded with the bright yellow discs of dandelion flowers, cowslips clothing fields in a blur of pale yellow and white snow drifts of hawthorn blossom tainting the air with their pungent scent.

To complement this burgeoning growth come migrant birds, the birds of summer that descend from the night sky to earth, completing their long migration from Africa, to surprise and delight when they are discovered singing where the day before was silence. I speak of warblers in particular. This year will be remembered for the wrong reason but to me it will always remain remarkable too for the prolific numbers of our commoner warblers. Every species I usually find along the path is here in unprecedented abundance. Garden Warbler and Blackcap, Common and Lesser Whitethroat. Willow Warbler and Chiffchaff, Reed and Sedge Warbler, all abound.

But it is to one warbler species in particular that I look most favourably. The Sedge Warbler is for reasons I cannot explain the most alluring. Possibly because it is not so reticent at showing itself compared to the other warblers but no, there is more to it than that. 

They are not uncommon and their breeding distribution is extensive, covering the whole of Europe including Scandinavia then east as far as western and central Asia. Their winter distribution in sub saharan Africa is similarly extensive, stretching from Senegal in the west to Ethiopia in the east and then down as far as South Africa.

They generally prefer somewhere that is damp or wet to breed such as here near to the river and this year I am overjoyed to note their abundance. Every small stand of reeds by overhanging bushes seems to harbour one, singing garrulously, hidden within feet of me as I pass by. Others sing from rank herbaceous ground yet to be greened by emerging nettles and grass while others sing from low in bushes.They are everywhere.

Each year the Sedge Warblers come to claim territories by the river and most will cease their singing and slip deeper into cover when they note your presence but always there will be one that seems to defy natural caution and will remain visible, allowing you to come close. Very close. This in itself feels a privilege as it is so unusual, a gift bestowed by the unwitting bird and bringing a special experience that will be long remembered.

One such Sedge Warbler, close to the path that meanders along the river's bank has taken up residence in a small area of rough herbage, dead grass and stalks and has commandeered a protruding stick, you can hardly call it a branch, to use as a songpost. 

Fully aware of my unconcealed presence just yards away it shows scant concern about my close proximity and continues to sing loudly from its perch.

If it is not there when I arrive I stand quietly, listening to other Sedge and Reed Warblers singing nearby. Five, maybe ten minutes pass and he flies in and dives into the vegetation below his favoured song post. Then he commences chirping, relatively quiet and conversational to begin with, as if tuning up before bursting into full voice. The song is hardly the most melodic and was disparagingly described by John Walpole-Bond in A History of  Sussex Birds as 'an incontinent grating babble' and T.A Coward in Birds of the British Isles as 'varied, irresponsible and erratic; it is difficult to describe'. 

The singing of the hidden warbler increases in volume and complexity as, at the same time, he rapidly ascends, by a series of hops, to perch brazenly and openly at the very extremity of the protruding perch. His singing increases ever more in volume as he goes into a paroxysm of song, the notes for the main, scratchy, harsh and grating and others, in the minority more melodic, all poured forth in a torrent with occasional mimicry of other birds contributing to this riot of a song. The sounds of a swallow and a whitethroat's alarm call are clearly discernible, the warbler's whole body the meanwhile, shaking with effort when at the peak of delivery. With bill open wide, revealing a bright mini cavern of vivid blood orange, he turns his head in every direction to broadcast his presence. At the height of his nuptial fervour he will take off and rise to twenty or so feet off the ground with wings and tail spread, briefly describing a circular or semi circular flight before descending, usually to where he took off.

Dissatisfied he will reverse position on his songpost, facing the other way to make sure all points of the compass benefit from his singing. He stops to listen, quiet for a few seconds and then, as another Sedge Warbler commences singing nearby, he embarks on another extravagant bout of song and so it goes on. 

Occasional forays into the willow carr of the adjacent Pinkhill Reserve interrupt the flow but it is not long, just minutes, before he returns, singing loudly as he arrives.

He has been singing thus for almost two weeks now and as Sedge Warblers continue singing throughout the breeding season until late July, it is difficult to tell if he has attracted a mate, or have any of his near neighbours that are also in full song. However, as he is still making song flights it would suggest he has not, as such flights cease when a male finds a mate. The females generally arrive later than the males but they should be here by now. If effort and sheer enthusiam are the criteria a female Sedge Warbler seeks in a suitable partner this individual should encounter little problem in finding a mate although it is said females show a preference for males with the most varied repertoire in their song.Whether my favourite has such a repertoire I cannot tell but maybe not if he is still having to make song flights.

His plumage matches that of the riparian habitat that is a Sedge Warbler's preference. A combination of streaked, brown and buff upperparts with a noticeable unstreaked tawny rump, the underparts a dull creamy white suffused with buff apart from a pure white throat. It is his head that is the most strongly marked, patterned each side by a conspicuous cream eyebrow, the supercilium, made more prominent by its contrast with a black crown above and thin black eye stripe below.

I watch him in silence, almost in reverence, musing on this tiny bird delighting me here in a corner of rural Oxfordshire and that has travelled thousands of miles from a winter home in southern Africa, defying immense odds to survive this far and take his chance at attracting a mate and producing another generation. A Sedge Warbler's life is not long, two years on average, as the hazards are many that beset it, especially for one that has to annually cross sea and desert twice to survive. I can recall many years ago in late April, when seawatching off Newhaven breakwater in Sussex, which extends a quarter of a mile out to sea and in the early morning watching exhausted Sedge Warblers and other small migrant birds finding salvation on the rocks at the end of the breakwater, too exhausted to go any further but after a long spell of rest they would depart inland.Those were the fortunate ones.

As it sings before me I stand and wonder at this warbler's existence and wish to possess its freedom of movement, its lack of worry and capacity to think, driven only by instinct to perform wonders that even to this day we cannot quite comprehend.