Expected flood of incoming birds is only a trickle so far
It seems somehow as if Rachel Carson’s prediction all those years ago in the 1960s which was manifested in her book, “Silent Spring”, has this year come true, albeit that in fact there is plenty of birdsong coming from the more sedentary birds - a bold merle seems to have usurped the mavis as the leader of the chorus here.
However, the expected flood of immigrant birds is as yet no more than a trickle. Where locally there has been for days on end but a single swallow where normally there are dozens, over the last week it has become a meagre five although so far there are none here!
Nevertheless I am encouraged by the growing volume of willow warbler music I am hearing and there are, therefore, some new arrivals moving in.
Rachel Carson’s work was seminal in every way for it was she who fully uncovered the damage pesticides, like DDT in particular, were doing … literally poisoning the landscape. She was a real pioneer and thank goodness those in authority listened to her. DDT was banned! She certainly lit a red warning light and thankfully it was heeded.
I was therefore very glad to hear that the European Union is to ban the outdoor use of neonicotinoid pesticides - substances often reported as being very harmful to bees - by the end of this year. This decision has come after an assessment confirmed two months ago by the European Food Safety Authority regarding the risk they posed to insect life in general but especially to bees.
The decision was hailed as a ’beacon of hope’ for insects which, of course, has the knock on effect of perhaps being a turning point that will be immensely beneficial to countless birds, especially migratory birds, most of which are insect eaters.
There was another red warning a week or two ago when, as I mentioned in this column, it was disclosed that French scientists believed that up to 80 per cent of insects had disappeared from the French countryside due to the heavy use of pesticides.
I just hope that the stable door has been shut soon enough! The primary benefit we derive from insects, including bees is, of course, the vital pollination of plants, including farm crops. We should always be mindful of the fact that we, the human population, are at the top of the food chain. In other words, the buck could eventually stop fatally with us! The warnings are clear enough.
Of the 11,000 species of birds that exist in the world today, more than 10 per cent of them - more than 10000 are either endangered or their future existence is threatened. This is our early warning system. Thankfully, scientists now have a much better understanding of the implications that declining populations of birds have for all life on this planet.
It has been estimated that as many as five billion birds leave Africa and head for Europe every spring. However, the lack of migrants in this airt thus far may not necessarily be down to pesticides so much as the current placement of the jet stream and the fact that there are still cool winds deterring insects from emerging, which in turn is a discouragement to migrating birds. The jet stream seems to be situated well to the south of us which, as I understand it, means that we are in a zone of cooler air.
In other words the un-spring-like weather caused by this phenomenon is the real culprit. And although I have always considered the sweet music in the form of that lilting cadence down the scale provided by the willow warblers is a guarantee that summer is on its way, it is certainly making slow progress at the moment! Warmer conditions, should they finally occur, may perhaps change things in an instant!
The other early migrant I always look for is the wheatear, a bonnie little bird, especially the male, boasting a blue-grey back, black cheeks and wings and buff underparts. The main physical feature of wheatears, however, is the white, flashing rump, prominently present in both male and female which makes these immigrant birds very easy to identify.
They are particularly familiar to hill walkers as they prefer moorland areas in which to nest, either in rock crevices, dry-stane dykes or abandoned rabbit holes. Despite the name of the bird, a wheat field is the last place you would expect to find a wheatear. Indeed, its name is a relatively recently devised one and literally originated as ‘white arse’, a singularly descriptive name! However, it is not one of the great songsters for although it issues a selection of quite mellow notes they are mixed up with little bursts of rather scratchy offerings with some additional quite loud chacking, especially if the bird is disturbed or alarmed.
Wheatears often dwell in the same sort of places as cuckoos but as they generally hide their nests in those little crevices, rabbit holes and dykes, they are not as easy to exploit as the more open, ground situated nests of say meadow pipits.
In this area these fairly anonymous little brown birds are probably the most numerous victims of the dastardly cuckoos which, of course, never rear their own young. Indeed adult cuckoos probably stay here for less time than any of the migrants, arriving in April – there are currently reports of them locally – and departing as early as July.
The female cuckoo deposits a single egg – always resembling those of the chosen host - in as many as a dozen unsuspecting pipit’s nests, leaving the entire processes of incubation and rearing to those unfortunate and involuntary foster parents. Not only that, but young cuckoos also instinctively tip out the eggs of the hosts. If any do hatch, the ensuing youngsters go the same way.
These young cuckoos have concave backs which enable them to gather and tip out both the pipit eggs and the young pipits. Therefore, the cuckoo ends up as the sole occupant of the nest and thus gets all the attention and food it needs as the foster parents work their feathers to the bone in order to sustain their single ‘off-spring’ which soon dwarfs them!
All these migrant birds may have their origins in Africa but as the ice retreated at the end of the last Ice Age, they began to explore the new world that was uncovered. However, clearly there was not enough insect food to sustain them during the winter months and thus migration evolved.
Currently the coolness of the winds is unfortunately still depressing the emergence of insect life but I remain hopeful that the jet stream might revert to a more northerly station and that therefore more and more of these migrants will eventually turn up.
Yet time and indeed timing, are of the essence, which may well throw some of them out of kilter, for trees are also late coming into leaf and thus the caterpillars so important as a food source for young birds may also be later than usual or indeed unusually scarce!
Meanwhile, my sunflower hearts are still disappearing like snow off a dyke!