The conservation and heritage charity for the
Loch Lomond and The Trossachs National Park

Weekly Nature Watch

Weekly Nature Watch 30 Aug 2019

on .

The signs of the passage of the seasons are undeniable. A horse chestnut in punk rocker-mode, its crown distinctively reddening tells us that summer is slowly on the retreat and that autumn is already peeping over the horizon. Town rooftops have fallen silent too with the sudden departure of the ‘devil birds’ – the swifts, which poet Ted Hughes described as, “… Jockeying across each other on their switchback wheel of death they swat past, hard fetched.” Swifts do not hide their lights beneath bushels, they scream and hurtle, and always, it appears, at ninety miles an hour. But now they are gone on their epic new race, all the way to Africa.

Swifts, therefore, do not stay with us for long. They announce their arrival vociferously and, as always, by hurtling among the town chimney pots in mid-May. They produce a single brood and by mid August are already re-tracing their aerial steps back towards the Dark Continent.

Yet cuckoos are even shorter-term visitors. They usually arrive in these northern parts of Britain in May. But by July, the parent birds are also already beginning their return to that same Dark Continent. Of course, they don’t rear even a single brood of their own but leave the job to unknowing foster parents. Furthermore, they depart without a care for the progeny to which those foster parents will be utterly dedicated. The hard working, long suffering foster parents are completely ignorant of the fact that the youngster they are energetically raising will have murdered their own natural young!

Meanwhile, other migratory birds are already preparing themselves for the hazardous journeys they must make during the next few weeks, also mainly to Africa. Preparation is largely about eating! Most will have acquired a new set of feathers so that they are prime condition to take on their mammoth journeys. But now they must stock up with body fat – the fuel they will rely upon to sustain them over their journeys of thousands of miles. The fuel comprises of subcutaneous fat just below the skin, a vital ingredient whether their travels are done in stages or not. For example, some warblers usually weighing in at 12 grams or 2/3 of an ounce, during late summer will add up to four grams as a means of sustaining them over long sea crossings such as the Bay of Biscay. And once they have completed that leg of their journey and made landfall in northern Spain, they will pause to add further fuel, sometimes as much as another ten grams, before tackling the daunting crossing of the Mediterranean and then the even more daunting, soulless Sahara Desert.

As you might imagine, they are required to prepare themselves as thoroughly as a Marathon runner, not only adding that vital fuel but getting their flight muscles in tip-top order. The miraculous fact of autumnal migration is, of course, that among the millions of birds that undertake it are young birds hatched during this summer. What a challenge that must represent to this new generation! There is preparation afoot also, not just for forthcoming winter but for next spring. The thistles, which just a few short weeks ago, were covered by bees and butterflies, collecting vital nectar, have gone to seed. Their heads are now a mass of white gossamer-like seeds, which are designed to take the progenitors of new life to fresh sites wherever the vagaries of the winds will take them.

Together, with dandelions and rosebay willow herb, a percentage of these floating masses of seeds, will find soil where they can begin a new cycle of life. Nature has many ways of promoting the creation and dispersal of life. She constantly seeks to colonise new ground albeit that this method of distribution is of course utterly random. Meanwhile, instead of butterflies and bees, those same thistles were the other day covered with goldfinches, both colourful adults and this summer’s crop of youngsters, yet to become red faced. But displaying as much agility as their parents, they extract the said seeds dextrously, like little trapeze artists, sometimes finding themselves upside down as they carefully prise out the nutritious seeds!

Goldfinches are always a delight whether feasting on thistle seeds or flitting in undulating flight from one patch of thistles to another, their whispering little contact calls a constant reminder of their presence. During the summer their vocal range becomes more ambitious. It is easy to understand why goldfinches were among the most prized birds when the keeping of birds in cages was fashionable. They are, of course, very colourful and attractive but they were also valued as fine songsters. Indeed, it was common during the second half of the nineteenth century, for regular competitions to be held with prizes on offer for the best singers as well as for the real good lookers. Really good-looking birds which could also sing sweetly were not only highly prized, they also changed hands for surprisingly large sums of money!

Such was the popularity of this cruel hobby that in 1860 it was reported that as many as 132,000 goldfinches were trapped in the south coast resort of Worthing alone. Indeed, so severely did goldfinch populations fall as a result of catching so many of them that the Government of the day brought forward legislation to protect them. The Protection of Birds Act of 1880, at least brought the force of law as a means of focussing attention on the plight of goldfinches in the hope of restricting this cruel trade. Although initially the law was largely ignored, eventually the notion that this was a cruel way to treat wild birds began to dawn.

Fast forward to the modern day and at a time when many birds are struggling to maintain their numbers, goldfinches happily seem to be prospering. Most of the migrant birds currently fuelling up for the journeys they will instinctively make in the coming weeks are, of course, insect eaters. They come here to feast on our insects and rear the next generations. But as autumn and then winter descend on these northerly locations, insect life rapidly diminishes so hence the mass migration back to insect ridden Africa.

However, there is one migrant, which in recent years has been bucking the trend. More and more blackcaps are choosing to winter in Britain. There have even been blackcaps spotted in gardens in Inverness in mid-winter. The secret of this strangely successful change in habit is that they have learned to feed on berries and on birdseed. In our eagerness to attract birds to our gardens during the winter months, we seem to have changed the blackcap’s diet as well as its migratory habits. This wee warbler, instead of undertaking that hazardous journey to Africa, may turn up on a bird-table near you! Perhaps it will join the charms of goldfinches - I like birds that defy the odds!

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

Richard Louv, Last Child in the Woods