Monday, 11 April 2016

Tom Langlands - Dwindling Murmurations

Gretna Green is famous for its weddings and the huge visitor numbers that descend upon the area as a consequence. Humans apart, there is another massive influx of visitors to Gretna Green every year - or at least there has been up until now.

For decades, and probably much longer, one of the largest gatherings of starlings in the country took to the skies over Gretna to perform their amazing aerobatic displays. Known as murmurations, these swarms begin with the onset of colder weather when smaller flocks of starlings, which are often seen in the surrounding countryside, come together to form bigger groups. Toward the end of October and heading into November the groups get ever larger. The phenomenon starts as daylight fades. Flocks of a dozen to several hundred birds head towards the Gretna Green area. Some arrive from the nearby Solway Coast and farmlands while others have travelled over 20 miles.

As the sun drops over the horizon the display begins. It is a mesmerising show of twisting, turning, swooping shapes. The flock goes one way and then another. Several groups break in different directions before turning and converging again at considerable speed. Watch the shapes and you can see stars, dolphins, dragons and fish silhouetted against the sunset. As the minutes pass the murmuration gets lower in the sky. There is little chatter, only the swish and flutter of over two million beating wings. This is an air show. It is nature’s theatre.

Murmurations begin slowly and high in the sky. The individual flocks merge. Within half an hour the sky darkens as hundreds of thousands of starlings arrive from all directions. At the start of the murmuration season most of the birds will be British but as the cold weather hits other parts of northern Europe and Russia they are joined by huge numbers of foreign visitors. It is estimated that at the peak of the Gretna Green murmurations there would have been between two and three million birds in the sky.

As they drop towards their chosen roost site the swarm spirals and condenses. Then it flows like black ink down a funnel. In minutes the sky empties and from the trees and hedgerows the noise starts; the amazing chatter of hundreds of thousands of birds. In the morning small groups of starlings head off in different directions in search of food only to gather again the following evening. Subject to weather, this pattern continues throughout November, December and January until the birds finally disperse toward the end of winter.

So, why do they do it? In part it is about protection as it is difficult for raptor predators to attack starlings in such huge numbers. It is also suspected that it is about information exchange. Birds returning from good feeding grounds can pass the word to others thereby offering the entire flock the best chance of survival.

Also, starlings are temperature sensitive and in order to retain body heat they like to gather in large groups. When roosting in the trees on very cold nights several individuals will drop off their perches and die simply because they did not get a good enough spot in the thick of the roost or because they failed to find enough food during the day. What many people don't realise is that starlings once disappeared from almost the whole of the Scottish mainland around 1800 on account of a very low and sustained temperature drop. The birds only returned from northern Europe and England when the climate began to warm again.

Despite these historic, massive gatherings starling numbers are falling rapidly with an 80% decline between 1970 and 2010 but with an even more worrying 50% decline between 1995 and 2010. In other words the rate at which starlings are disappearing is increasing and that is a trend that is still continuing. Because of this starlings are now on the ‘red list’ species, i.e. of highest conservation concern.

The reason for the decline in numbers of this once common bird is not fully understood but it is likely that loss of habitat through modern farming techniques plays a significant part while previous generations of city-dwelling starlings were driven out as pests. It is sad to know the numbers are falling, for the spectacle they provide is one of nature’s truly magical moments. I think back to the days of runaway marriages and wonder how many love-struck couples were guided to Gretna Green, in fading light, by the starlings performing above this small Scottish village.

However, this year has brought another change as the ever dwindling number of starlings has now relocated its roost to the Kingston industrial estate in Carlisle. Given what we know of starlings that is perhaps not surprising. With dwindling numbers it gets ever harder to stay warm on cold nights and an industrial estate is a source of heat - from buildings, street lamps and vehicles. Sadly, we may be witnessing the last of Gretna's starling murmurations and the beginning of the end of these incredible spectacles of nature altogether.

Tom Langlands

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