One of the slightly unusual characteristics of this benign summer has been the constant presence of breezes. Indeed, one way or another, it has been a pretty windy summer. However, that has at least ensured that there has almost always been plenty of movement on the loch, especially last weekend when white horses were galloping across the restless waters before dashing themselves on to the stony shore. One of the benefits brought by the wind and waves has been the absence of deadly algae clogging up those waters. Thus it was that last weekend provided rare entertainment for those who enjoy watching birds, albeit that the strong wind ensured that some birds were made to work that bit harder for their suppers.
And there were those however, which showed a real appetite for using that same wind as a vehicle for fun. Ravens, rooks and crows, despite their perceived mundane appearance, not to mention the reputation they have as rather 'dark' birds, in more senses than one, are nevertheless superb aviators. And when they get the wind under their tails, they produce some really breathtaking displays. Carrion crows are not particularly sociable birds and so usually perform in pairs or family groups. Ravens too, whilst lacking the group mentality of rooks, are very capable of performing some amazing aerobatics, also often in family groups, corkscrewing through the air, flying now and again upside down and showing a real talent for some amazing aerial stunts.
Rooks, perhaps the scruffiest looking of the corvids, are, because of their preference for corporate life, entirely different. They often seem sufficiently inspired by the wind to come together in great swarms, to hurtle across the sky in what may seem to be confused disorder. In reality, these gatherings might instead, be described as anachronistically as ordered chaos! Their mass game-playing - games resembling tag and catch as catch can - which may include conducting headlong, seemingly suicidal dives, ending with dramatic, superbly timed recoveries and pivots. These many variations on an aerobatic theme are the hallmarks of these amazing performances. Suddenly the sky is full of dancing dervish rooks!
I always think much the same of gulls. They too seem to revel in defying the wind gloriously if not quite so corporately. All of us I'm sure will have marvelled at the sight of gulls zooming nonchalantly among and amazingly close to the foaming, pounding waves of our seas on the wildest of days, literally dodging the advancing rollers. They skim so close to the churning, boiling water that they seem to be in danger of being swallowed up and swamped by it. But they never seem to put a foot, or rather a wing, wrong. And, as there does not seem to be any practical reason for them to challenge the conditions so, one is forced to conclude that, as with the aerial antics of the rooks, they are performing these daring flights, simply for fun ... and maybe as a challenge to be met!
However, the heron I watched battling with the wind last weekend, certainly did not have fun on its mind as it was repeatedly buffeted by a strong westerly. It rose from the loch-side calmly enough but once it had cleared the shelter provided by the trees, it found itself unmercifully tossed to and fro like a piece of flotsam, finding progress at times rather more than a little difficult. Having spent a fruitless period at one station, it had clearly decided to try its luck elsewhere, only to find its journey punctuated by brisk gusts of wind, which seemed determined to halt its progress.
Herons are actually remarkably strong flyers due to having an extremely large wing surface in relation to an extraordinarily light body. When hawking was literally the 'sport of kings', herons were regarded very highly for being excellent quarriers for the hawks. Herons, in good conditions, because of those large wings and such a light body weight, are capable of gaining height very quickly thus providing excellent sport for the hawkers' peregrines which usually try to come at their prey from above. Herons offered a real challenge to this form of attack and consequently often managed to escape those onrushing, crushing talons. But when the wind blows, these advantages are turned into liabilities.
And of course, when the wind blows with such force, some birds of prey also find it difficult to employ their normal hunting tactics. For instance, kestrels find hovering a very tricky proposition in these conditions. Although other raptors such as the buzzard, the kite, the osprey and to some extent the barn owl also use the hover as a means of spotting prey, none perhaps show quite the expertise demonstrated by the kestrel.
I have in the past, compared the hovering of a kestrel, with the computer driven flight of a modern airliner. If you are in a window seat on such a flight you may be able to watch the wing flaps of your aeroplane and you will notice that they are constantly yet subtly moving up and down. This movement is in response to the on-board computer systems, which are constantly monitoring the plane's exact position in the sky, enabling it to make those minute adjustments to maintain its equilibrium.
In a sense, the kestrel's brain is performing the self-same task. If you are able to watch closely a hovering kestrel you will soon become aware of similar responses in the wings and tail of the bird always making those precise adjustments in response to the conditions. In fact I am sure that every sinew and every muscle of a kestrel seen this week, struggling to retain its position in the wind was, like the wing-flaps on the airliner, responding to the virtual computer that is the bird's brain! The result was poetry in motion. And naturally, if the wind is blowing hard, those responses have to be even more instant and precise. In such circumstances, they are indeed a wonder to behold.
The key for the hovering kestrel is that the head must be kept as still as possible in order that the bird can focus as it scans the ground below in detail for the movement of its prey. Kestrels depend heavily on small mammals such as voles and mice as their main source of food. This brings in to play the other vital component part of the kestrel's armoury, its eyes. If you were to compare the eyes of a human being with those of a kestrel, relative to the size of the skull, then we should have eyes the size of tennis balls.
The eyesight of a kestrel is thus so much better than our own but then it needs to be, for it has to seek out those minuscule creatures far below, well hidden by the vegetation. Voles make little runs through the grass, which they use regularly. They are like little covered walk-ways and that they hope makes them less conspicuous. The kestrel's eyesight however has to be sharp enough to see through that cover.
There is a special place in my heart for kestrels for when I was but a lad in short pants. I used to regularly lie on my back in 'my special field' watching larks soaring but more dynamically perhaps, having a worm's eye view of hunting kestrels hovering. I thought then, as I think now - is there a more magnificent sight in nature than this? I remain convinced there isn't! And when the wind blows, their command of that hover is even more amazing! Simply gyroscopic!