Sunday, 29 March 2015

Heraldic Bluethroats

Bluethroat (Martin Kelsey)
It was the white spot which made us gasp. As it turned to face us, standing with elegance with its long legs, drooped wings and cocked tail, the male Bluethroat transformed. Having shown us its hind view, predominately a grey mousy-brown, with an orange base to the sides of its tail, face-on the difference could not have been more startling. It bore a throat and breast of pure sapphire, carrying a broad darkish band below which untidily merged onto an even broader dark brick-coloured cumberband. But what drew our gaze was its badge of immaculate white, centrally placed amidst the blue. It was almost reflective in its quality, like a medallion, illuminous even. It was hard to think of feathers being the medium for this - it was more like an inlaid little mirror in a Rajasthani embroidery.

 Bluethroat (Martin Kelsey)
I had a fondness for this particular Bluethroat, as I have watched it many times over the last few months, as it fed within its little winter territory, making mouse-like scurries across patches of open ground and pausing, as if to take its breath, upright, with tail held high. It was frequently embroiled with chases with its neighbour - another male, but not as smartly-plumaged as this one. It has been bold and engaging each time. But there was something different today. As we arrived, I heard a short burst of its song from deep in the Typha cover. A song of special places and memories for me....from Bluethroats atop montane broom high in the Gredos Mountains of Spain, to a walk I took beside the Indus River in Ladakh years ago where Bluethroats were singing every few strides I took. But what made today's reunion different was the spring sunshine touching its colours, which were the freshest and brightest I had ever seen them. This male had now completed the partial moult of its head and breast and slowly, imperceptively, over the last few weeks had replaced its feathers there. It was now ready with its pristine, fresh heraldic colours, and its song, to start its migration back to its breeding grounds. I wondered if this would be the last time I would watch him.

The white-spot on the breast told me that his destination would probably be somewhere in Central Europe and studies suggest that this is the origin of the increasing numbers of Bluethroats now wintering in Spain. It has become a bird quite easy to find despite its generally skulking behaviour (which reminds one that it belongs to the same genus as the nightingales) in marshy areas in winter here, especially also in the ditches beside rice fields, often betraying its presence with its tucking call, reminiscent of the sound of barbers' scissors snipping away. But what made this equinoxal encounter so special was to see this gorgeous character, completing its winter sojourn with us, now dressed fresh for spring and clearly poised to embark to another similar sized territory, perhaps two or three thousand kilometres to the north. I wished him well.

Tuesday, 10 March 2015

Jigsaw spring

My first Woodchat Shrike of 2015 (Martin Kelsey)
The jigsaw puzzle that is spring is starting to take form.....every year there is the overture, embracing the exodus of Common Cranes in late February with a dramatic arrival of a first wave of summer visitors. A natural remedy: if we feel bereft at the departure of the winter soundscape of bugling cranes, so the enchantment of months' of engagement with the delightful Lesser Kestrels is gifted to us. Thus by early March, with merely a rump of a few dozen cranes remaining from the tens of thousands, Barn Swallows are already collecting mud for their nests and Short-toed Eagles hang in the sky, as if fixed for the emergence of their serpentine prey from hiberation. The gentle caressing fluty Blackbird song starts and closes the day. The pieces of the jigsaw puzzle fall, in an orderly sequence into place, species by species. The timing, phenology, of arrivals and departures fascinates all, for motives ranging from the science of evolutionary adaptation to the wider marking of the passage of seasons, with birds such as the first swallow or cuckoo being intimately entwined into our own heritage. Broadly both the sequence of arrivals and their timing are predictable, with most birds using that most constant of cues, daylength, to trigger migration. Thus, as I set out to wander in the dehesa around the Alcollarín Reservoir yesterday morning, it was a joy but not a surprise, to direct my vision towards a scratchy, almost incoherent warbling coming from the top of the holm oak nearby and seeing my first Woodchat Shrike of the year, the March sunshine making its crown appear like carefully nurtured mahogany. As it quietly chortled, two male Hoopoes incessantly bounced their "uup - uup" calls against each other, like acoustic ping-pong.

There is variation of course, brought on by prevailing weather, or the physical condition of the birds themselves. Cranes will wait for a sunny day with little wind to set off north-east out of Extremadura, anytime in the second half of February. The perturbations to normal patterns add spice to the observer of course. Over the last few days there has been an unusually large passage of Garganey through Extremadura, with drake-dominated parties of twenty or even thirty birds turning up at water bodies across the region. On a brief visit to Alcollarín three days ago, I watched 23 birds, males stiffly bobbing their heads, giving their rattling display calls as they weaved and swerved around the out-numbered females. I could have happily spent hours watching these, my favourite of all ducks.  As during my early birding years in Britain, there is an exotic ephemeral element to Garganey, wintering in tropical Africa, they make brief appearances in early spring on sometimes the most modest of pools. Two days later, just before watching the Woodchat Shrike, a careful check of the reservoir revealed just four Garganey left: three drakes and a duck.

Through natural selection, there are changes happening with migration timing and direction. With climate change and the shifting forward of annual cycles of many plants and insects, there can be a selective advantage on those birds which migrate earlier, to keep up as it were with the supply of resources on which they depend. As well as individual differences, there are differences too between species on how flexible or adaptable they can be. Reed Warblers are now returning to breeding grounds in Europe 14-21 days earlier than they did 40 years ago, whereas Great Reed Warblers with their longer migration routes are only arriving a few days earlier than before.

Great White Egrets (Martin Kelsey)
I paused and watched a line of Great White Egrets on a weir. Another example of change, I reflected. Formally a great rarity here in Spain and across Western Europe, its spread from the east has been exponential. One of the birds (the right-hand bird in the picture) was colour-ringed, probably (but this will be confirmed) in France. Through the traditional ringing but especially now with satellite-tracking and other technology, we are slowly starting to visualise better the movements of birds, not just the starting points and their destinations, but most intriguingly what they are doing on their travels as well.