When the first hint of spring is felt in those pioneering rays of sunshine that take the edge off the winter chill our property undergoes a transformation. Ventilated by airbricks when built each spring these cleverly constructed pathways through the walls provide the perfect safe space for birds to nest. Popular with sparrows and members of the tit family their presence is soon heard in the disembodied frantic chirping of hungry young that ebb and flow as you walk along the length of the wall. It as if the building has responded to a medical emergency by the construction of a maternity field hospital of nested beds, complete with a nursing staff of frantic parent birds who provide a never-ending stream of catering, security and cleaning services.
One evening we find a tiny baby chick squirming on the gravel below the airbricks a victim of overcrowding or sibling rivalry for food. Too young to be fed on the ground by a parent bird its’ only chance of survival would be to locate the nest and return it as quickly as possible. This was not going to be an easy task. We were staring at a wall with at least 120 air bricks in total with 28 in the area above where the chick was found, and our sudden interest in and proximity to the wall had resulted in a wary distancing by the parent birds. They watched desperately and vocally from a distance; torn between the conflicting instincts of wanting to feed their young while at the same time protect them by not revealing exactly which brick their nest was concealed behind.
We moved away from the wall, sat down and waited for the parent birds to return. In silence without book or phone the time passed; a moment often lent but seldom grasped. After twenty minutes, a bird could not ignore the demands for food any longer and flew back to a brick and we had found our nest. Easing the brick out of the opening a cacophony of shrieks, very vocal threats and well-aimed spitting greeted us. Instinct meant that this bird despite being the overwhelming under-dog had to take us on; the well- placed pecks to the hand that it landed before the chick was safely returned were a painful testament to a willingness to fight any invader.
Instinct and bravery are by-words for our other much anticipated and looked-for summer visitors: the house martins, swallows and swifts. Much to our distress when we first moved into our property the necessary building work scared off these summer migrants. The following year we were more careful making sure that the top part of the outbuilding door remained open, and thankfully after that the swallows came back year after year. Summer evenings are filled with their agility and grace as they sweep low in search of food in a beautiful aerial dance. It is an absolute pleasure to watch their airborne master classes: swooping low to the ground at high speed, and then with no interruption pulling up at the last moment to bank at the steepest of angles.
It is difficult to comprehend how such tiny summer visitors to our shores can fly the 6000 miles from South Africa where they over winter; crossing the Sahara and into Europe through France and Spain at a rate of 200 miles a day to return to the same nest sites generation after generation.
Today we know about migration, and although technology allows more access than ever to the journeys these birds take each year it was not always so. To find out people employed the starting point for all the best science: they noticed something and would not let it be. What they noticed as they studied the birds was that certain ones at defined times of the year would simply disappear from our shores only to miraculously reappear again later. They determined to find out why and where they went. When I read about things like this I always like to hope that I would have noticed too.
Being born in Staffordshire I am proud that it was in my county in 1911 that John Masefield, a Victorian solicitor from Cheadle in the shadows of the Peak District, found out that the swallows he saw leave in the autumn spent their winters in South Africa. He knew this because he had been informed by letter that the swallow on which he had placed a small addressed aluminium leg ring had been caught in Natal, so far south east in Africa that unbelievably the most direct route meant the swallows must have flown across the Sahara.
The simple solution of ringing had established the destination, but still unanswered was why these birds insisted on such an extreme and sometimes fatal journey.
Are the birds shown the route by their peers, or has a taught behaviour become a learnt behaviour; an instinctive response to seasonal change? We are always concerned if “our” swallows insist on one last brood; we know that the clock is ticking and that the parent birds will leave even if their young are not strong enough to follow.
Early experiments found that caged birds prevented from migrating continually hit the same side of their cage to fly away even when the magnetic field was interfered with. Schools of thought on migration are divided into those of calendar and weather, as well as memory or genetic. Today’s advances in technology act as a double-edged sword: providing answers but also generating more questions.
We can identify with this instinctive response to a seasonal change, although maybe not to the life endangering extremes of these birds, when our behaviour alters in line with the seasons. Just as the migrating birds are drawn to the sunshine and the benefits it offers, human post- surgery recovery rates improve when patients are exposed to more intense sunlight, and for some people sunshine reduces painkiller usage and stress rates. It is suggested that the brain chemical serotonin is boosted by exposure to sunlight. The reverse of this is Seasonal Affective Disorder(SAD) which is a type of depression that comes and goes in a seasonal pattern with symptoms more apparent and severe during the winter.
In early autumn, the power lines are overloaded with birds impatient to start their epic journey south, and you are struck by their resemblance to the human queues in airport departure lounges; both eager to reach sunnier climates but also bracing themselves for the journey ahead. As always it seems that more unites us with than divides us from the rest of the animal world, although if it was possible those migrating birds would probably take a plane too.