Weekly Nature Watch 28th August 2020
The clock is ticking faster and faster as the last few days of August come and go all too quickly and time is getting shorter for our migrant birds.
Soon, the first of millions of them will be bidding us farewell as they launch themselves on improbable journeys, most of them back to the Dark Continent of Africa. During these next days and weeks, our skies will be emptied of summer visitors and later filled with the first of our winter ones. However, the season of change is already with us for the screaming swifts have long gone, their stay with us remarkably brief, just sufficient to rear one generation of youngsters.
Our local ospreys have also produced just one brood as usual, albeit that they take their time. Indeed, almost the entirety of their summer sojourn has been taken up with the raising of their young family. And how they have nurtured it. Much TLC has been expended upon the two youngsters that have been the apples of their parent’s eyes. From the moment they hatched in the untidy but cavernous eyrie atop a gnarled old tree, the parent birds have lavished their attention on these two chicks. At first the food they required was fetched solely by the male bird, with the hen brooding them assiduously but as they grew and the demand for food increased, she also had to do her duty and catch fish for them.
But any day now all that devotion will suddenly come to an end. After all the care and attention, in the next few days the parent birds will take off and not return. Without warning and individually, they will set sail for their African winter home abruptly breaking the bond between them and their youngsters. Those two chicks will face the awful truth that they are on their own although they too will be lured during the next week or two to follow in the wake of their parents and head for Africa. Whilst the parent birds have the advantage of knowing the route that they must follow having travelled it for a few years now, the young birds have nothing more than in-built instinct to guide them successfully to their distant destination.
The young ospreys nesting for the first time north of here at the Loch of the Lowes are certainly cutting it fine. Having deserted the original eyrie, they have built another where they have produced just one chick. This young osprey has only just fledged and the fear is that the parent birds may follow instinct and leave before their youngster has learned to fish. Such a situation could spell disaster for that chick and we await the outcome with bated breath.
Meanwhile, during these past few weeks since they first took to the air, the two youngsters here will have had to learn the art of fishing, will have learned to fly high above the loch eyes rivetted upon the water for the tell-tale movement of a fish close to the surface. They will have learned to hover and then commence that dramatic dive. They will also have learned the hard way that not every dive will bring them success, that sometimes, especially if the water is turbulent, they may have to try and try again in order to obtain a full belly. This is learning with a real purpose and achieving success is vital for their survival on the journey that now lies ahead of them – one of several thousand miles.
Amazingly, in their brains there will be the equivalent of a map that charts the route they must follow, down through England, across the English Channel and onwards through France and Spain. Another sea crossing of the Mediterranean takes them to Africa. There they will follow the coastline until they eventually reach their destination in Senegal or The Gambia. And of course, en-route they must keep their energy levels well topped up by catching fish, a skill they are currently desperately honing now and the most vital part of that learning process. This is what the last few weeks has been about, first watching their parents fish and learning technique from them and then perfecting that technique. Upon that depends the success or otherwise of their southbound flight.
Also bound for Africa are the legions of swallows and martins that I have been watching in recent days. They too have a daunting journey ahead of them. Earlier broods are already congregating prior to setting out on their marathon journeys. The swallows have an incredible six-thousand-mile journey to fly to the Cape of Good Hope – South Africa whereas the martins, although perhaps not travelling quite as far, have nevertheless a considerable journey of four or five thousand miles.
Currently, however, most martins seem still to have work to do judging by the frequency of their repeated visits to their nests in the eaves of a friend’s house. It was a muggy August day as I watched them careering low over a field that must have been fairly buzzing with insect life. Both swallows and martins were constantly plundering insects as they flew low over the rank grasses. The young broods of martins yet to leave their
nurseries and taste the excitement of flight, will, like the osprey chicks, have to learn the art of getting enough food by catching flies quickly if they are also to survive that enormous trek but at least they are likely to have guidance from their parents. House martins and swallows do not abandon their youngsters and leave them to find their own way to their wintering grounds but their route may be even more hazardous for they have the enormity of the Sahara Desert to cross, a desert which, by the way, sadly accounts for so many of them. That is why they may produce up to three broods of young during their stay here because the odds are clearly stacked against them and losses of these trans-desert travellers are known to be heavy.
Other migrants, having moulted out their old coats of feathers and renewed themselves with completely new plumage, are now well prepared to take on the massive journeys that lie ahead of them. I watched a willow warbler, resplendent in its new set of clothes, picking away at insects from the fading leaves of one of my damson trees the other day. And of course, this is when, in preparation for their massive adventures south, these birds must feed up and put on the ounces. This is the fuel that will carry tiny birds such as the warbler clan on their journeys. They will top this up where and when possible during their flight south because of the need to keep up their energy levels if they are to successfully negotiate the thousands of miles they must travel.
All this movement of birds presages the decline of our summer. We perhaps think only of our summer birds when we think of bird migration - those that summer here and winter in Africa. Yet waiting in the wings in the Arctic and Scandinavia and indeed, in Russia, there are legions of more birds waiting for the strangling grip of their winter to descend before looking in this direction for salvation. If here, there is an immense population of avian travellers foregathering in preparation to journey away from these shores to Africa, that other legion is waiting for the right time to come to these shores for the winter months.
It's all change - the skies across our globe are about to become very busy indeed!