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Loch Lomond and The Trossachs National Park

Weekly Nature Watch

Country View 16.8.17

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That sound of silence continues except for the twittering swallows and the melodic martins ... and one rather surprising voice in mid-August - that of a lone willow warbler. And there was no question, that sweet and gentle cadence down the scale, is unmistakable. On this occasion it was muted, a whispered, discreet little reminder of a song that had been so dominant in this and just about every other airt I visited, during this year's spring and early summer.

With the year's task of producing a new generation of willow warblers now fulfilled and a mute period called for whilst feather renewal is the order of the day, perhaps he has jumped the vocal gun prior to beginning preparations for his departure to his African winter home. Unlike other migrants, over the course of his sojourn there he will go through another much more prolonged moult over the winter months.

Whether this lone vocalist has come through the moult earlier than most and was thus letting the world know that he now has a pristine new coat of feathers I don't know. Perhaps it was just a 'feel good' moment? But I haven't heard him again. Perhaps that single, murmured phase was hinting at an earlier than usual departure, for instinct may already be influencing him to prepare for the mammoth journey he must inevitably take quite soon anyway.

Some birds have already departed these shores of course. Adult cuckoos abandoned their offspring to the care of their unwitting foster parents a week or two ago, to begin their southward migration before August was even on the calendar. I reckon town streets may fall silent during the next few days as the screaming swifts up sticks and follow the cuckoos to fly south ... rapidly!

Yet this year's crop of young ospreys is only just discovering the joys of flight, utterly unaware that they too will soon be drawn as if by magnets, to join the exodus. What they probably don't yet understand, is that their parents, thus far utterly devoted to their welfare, will, before the month is out, suddenly desert them and take off for Africa too, leaving their offspring to fend entirely for themselves.

It must be a very rude awakening for young ospreys. They will eventually and instinctively follow their parents but first they must properly hone the fishing skills by which they must survive during a forthcoming journey of some three thousand miles. It is only a few short weeks since they found themselves unceremoniously taken from their treetop eyries by tree-scaling humans, plunged into sacks, lowered to the ground, weighed, ringed and tagged, before being returned aloft. This procedure is routinely employed these days as a means of learning more about the lives of ospreys and their travels.

In recent years, many young ospreys have also been fitted with GPS tags so that they can be monitored throughout their journeys south. As anyone who has travelled to America will know, ospreys are endemic there. Indeed, in some parts of that vast country, they are extremely common and I well remember seeing eyries built upon man-made structures such as bridges, in Florida.

North American birds, as you might imagine, migrate each autumn to South America and a few years ago, a family of three youngsters was electronically tracked as they flew south. The biggest hazard these American birds encounter is the vast Gulf of Mexico. Two of the birds being tracked literally disappeared during that part of their epic flight, with only one of them surviving to pitch up in its South American wintering ground. Survival on such a hazardous journey is clearly a major challenge.

Whilst our ospreys do not have to cross such immense spans of ocean, they nevertheless also clearly face considerable challenges, especially as they receive absolutely no parental guidance and so have to rely entirely upon in-built instinct to navigate their journey successfully. I recall hearing a few years ago, of one young bird from this part of Scotland, which got its navigation wrong and ended up somewhere deep in the South Atlantic, rather than in West Africa.

Meanwhile, those newly fledged birds must in these next, crucial few weeks, watch and learn from their parents whilst they can. It is essential that initially, they watch their parents as they hunt and then try to emulate them. They must quickly sharpen their fishing skills in order to ensure that they are as practised in that art as possible before they eventually take the plunge and head for Africa themselves. Remember they will travel strictly as individual birds. It is indeed a daunting start in life for these birds but a challenge they cannot of course, resist.

The strong instinct to fly south, an instinct inherited by all our summer migratory birds, poses an interesting question. I have often been puzzled at reports I have read about James V1, when he became James 1 of England, which tell us that he deployed cormorants to fish on the Thames ... and surprisingly ospreys too. As ospreys, probably pretty common in those days, are such migratory birds, the drive to obey instinct and head southwards as the summer wanes must surely have been insurmountable. Did the king therefore, have to have ospreys re-trained each summer or did those birds perhaps simply perish in captivity?

Cormorants, sedentary birds of course, are still employed in this way, not of course, on the Thames but in the Far East, as many of you will know via the medium of television advertising. But I have found no information that suggests that ospreys are used as a means of catching fish for human consumption, anywhere in the world. I am sure that migratory instinct would always prevail if such a scheme were to be attempted with the likely demise of birds forced to remain in captivity.

Right now, this year's youngsters are cautiously finding their wings and making their first, probably most futile attempts at catching fish. Adult ospreys often have to make several attempts before successfully rising from the water with fish firmly clasped in talons, which are specifically adapted to configure in such a way so that two claws are back and two forward as opposed to three forward and one back as is the norm. This ensures a firmer grip on slippery prey. However, these young birds will inevitably be hard pressed to sustain themselves.

They must first learn to quarter the waters they are fishing, spot their scaly quarries near the surface, hover and then diver to hopefully grab their slippery prey before rising in triumph, pausing briefly to shake surplus water from their plumage. Thus, at first the youngsters are likely to find themselves very frustrated, failure more often than not being the norm. These August 'learning' weeks are therefore vital to their future survival.

While instinct will eventually kick in, the August training is nevertheless, for these newly fledged youngsters, literally, make or break! Should they complete their journey successfully, they will remain in the fish rich waters of West Africa for the first two or three years of their lives, honing those vital skills before returning here to the land of their birth.

Any natural place contains an infinite reservoir of information, and therefore the potential for inexhaustible new discoveries.

Richard Louv, Last Child in the Woods