The far-travelled warblers bring the sweetest sounds.
Each day brings further arrivals as migratory birds pile in, drawn as if by a magnet to what, over these past few days, has been a sun drenched landscape. Tiny fragments of life somehow propel themselves across thousands of miles and conquering many hazards on the way.
Over the Easter weekend, suddenly that whispering, down the scale melody, that is the hallmark of the shy willow warbler, was to be heard everywhere. Somehow, willow warblers in their thousands have crossed the vast Sahara Desert, the Mediterranean and the English Channel and in all probability two or three mountain ranges to boot.
And now they are here in numbers, ready, willing and able to prepare for the production of the next generation of willow warblers. For that is precisely what they come here for.
These improbable long distance travellers somehow provide one of the final avian buildingblocks that make certain that we are inexorably on course for summer. They, more than most, affirm the miracle that is bird migration. That sweet and gentle melody tells an amazing tale of the success of navigational accuracy together with degrees of sheer strength of will and courage in adversity not to mention determination, that is simply beyond our understanding.
How is it possible that these minute scraps of life can undertake such journeys? A willow warbler weighs in at less than an ounce albeit that in advance of this marathon, these fairly anonymous little brown birds with a hint of olive green about them, must gorge themselves upon the insect food that represents their entire food requirement. This is the fuel that will enable them to take on such a challenging journey. They will of course, top up their fuel tanks when and where they can en route albeit that those that take on the vast Sahara, will find the cupboard there pretty bare!
The willow warblers that head northwards from sub-Saharan Africa in the spring are destined for traditional breeding areas right across the Northern Hemisphere. Some will be arriving in Russia whilst others head for Scandinavia and for other parts of northern Europe and of course to here in the UK. It is thought that this single species, which has probably been on the move since February, may number as many as a billion birds making them by far the most numerous of the warbler clan!
Other warblers arrived here a few weeks ago. Chiff-chaffs, almost identical to their cousin willow warblers but differing in leg colour - the willow warbler's are flesh coloured whilst the chiff-chaff 's are black - is one of the earliest of the warblers to arrive here, their monotonous 'chiff-chaff ' call heard as early as late March.And amidst the growing avian chorus, I have also heard the rich voices of garden warblers, the archetypal 'little brown birds'.
The vocal competition is certainly growing by the minute. I sat in my garden at the weekend and was nearly deafened by my local merle, which although perched high in a tree in my orchard, sounded as if he was perched on my shoulder! There to, almost as a background sound, was the gentle voice of a willow warbler The blackbird seemed determined to out sing the great tits with their oft repeated and urgent two-note declaration, the chaffinches' chortling little songs and even the rapid vocal fire of Jenny Wren, which size for size, out does them all in decibel levels.
That wren certainly drowned out the warbler and the reedy but complicated song of the dunnock and even the quarrelsome sparrows were put in the shade. But how the air has filled with all these voices and it is as if our world has suddenly come to life. The hillsides glow with gorse and whilst the daffodils are fading, the first bluebells are appearing.
But it is those minuscule warblers that command my attention. All travel a similar route from sub-Saharan Africa, albeit that the attractive little songster, the blackcap, seems increasingly reluctant to make this hazardous journey, with more and more of them choosing to take advantage of recent mild winters to winter in southern parts of the UK. They are not numerous in this airt which is a pity for their voices, not unlike those of the garden warblers, are pleasant on the ear.
All warblers are fairly anonymous little birds, none of them strikingly coloured, just little bundles of nondescript brownish or grey feathers. Although a few have hints of green and yellow, the only notable features boasted by some are the eye stripes. These are particularly prominent in the aforesaid willow warblers which are also recognisable by their greenish hue. But the main distinguishing feature is their vocal contribution to the rising volume of music that now greets us on a daily basis.
However, warblers in general are struggling to maintain populations, with the whitethroat, once a regular summer visitor here, now seemingly absent. Also, so far I haven't heard the trilling of wood warblers but they too may be expected any day now. There is another warbler, which I well remember encountering during badger-watching evenings. Of course, I was then agile enough to climb trees, which I did regularly when on such expeditions!
I was in position nice and early - it was nearing midsummer - waiting for the badgers to emerge, when my attention was caught by a continuous trilling burst of music, which seemed to be coming and going, ebbing and flowing like some imaginary tide. Eventually I tracked the source of this seemingly mysterious ventriloquist down and once again it turned out quite hard to spot simply because it blended so well with its background.
But there perched in another tree, was this pretty anonymous bird - grasshopper warbler - which as it sang, turned its head this way and that. Hence the varying volume of its whirring song.
I certainly remember hearing them again when, quite close to where I live, a forestry plantation was developed on what was previously very boggy ground. A few years later, grasshopper warblers could be heard producing their ventriloquist's deceiving trilling. But once the trees had grown, their singing ceased as they had moved on.
Sadly, in recent years their populations have plummeted as indeed have other populations of warblers. Of course, they rely largely upon insects for food and therefore, recent reports of a considerable reduction in insect populations, is not good news for warblers in general. Such decreases perhaps reflect the over-use of pesticides especially in the western world, which may well be upsetting the balances of nature.
Not only do those tiny warblers amaze us as a result of their mammoth journeys, they add so much variety to the sounds of spring and summer.