Every spring I get a surge of excitement when I spot the first swallow of the year as they set up temporary homes here from around April to September  Not surprisingly maybe, they seemed to arrive later and are planning to leave earlier this year.

At this time of year I get a pang of sadness as I watch them line up on the telephone wires (another endangered species, incidentally and according to all the emails I’m getting from BT)) waiting to leave for South Africa – 6,000 miles away, for their second spring and summer.

It’s not difficult to see why they do it but how?  I have read several fascinating books that reveal their amazing competence and resilience but it’s still hard to actually comprehend.

The proverb, ‘one swallow doesn’t make a summer’, attributed to Aristotle, means that a single event doesn't necessarily indicate a trend. It can also be used to say that even though something good has happened, the situation may not continue and you can't rely on it.    

Sadly swallow numbers are in decline, with unpredictable weather patterns – in Africa, here and on their journeys in between - being blamed.  

A mixture of wetter springs and short summer droughts, lead to major falls in numbers of the flying insects on which they feed, and is thought to have reduced the swallow’s breeding population by almost a quarter in the past 25 years or so.

And a recent report confirms that the house martins and swifts, have suffered even greater falls in numbers over the past decade with our changing climate being blamed again.  But this is also alongside modern industrial agriculture being responsible for a huge decline in the insects needed to sustain these beautiful birds. Ironic really as swallows adapted to live alongside farmers, nesting in their barns, and feeding on insects attracted by their livestock.

As the swallows prepare to leave soon, flocks will include youngsters who’ve never done the journey before. Of course, they will have heard all about it from numerous relatives over the summer, but that hardly counts as preparation.  The adult swallows will lead the way, following their old, ancestral established migration routes and timings – but tragically is another thing that is being messed up by climate change.  The youngsters - first-year flyers, will follow behind their parents, sometimes lagging a few days, or even weeks, behind their Elders. Ornithologists suggest this may allow for a more organized and efficient migration that will ensure the survival of the flock.  

Right now, they will be trying to gorge on as many insects as possible to fuel them for their 6,000 mile trek between the UK and South Africa. The journey can take up to six weeks, with them flying up to 200 miles each day at an average speed of 20 miles per hour – occasionally hitting 35 miles an hour if the wind is in the right direction.  

Storms and gales are one of the biggest enemies of the migrating bird – and have been getting stronger and more frequent in the last twenty years or so.  On their mammoth journey, the swallows will stop briefly to rest and eat in their large flocks with favourite ‘take aways’ being large reed-beds – home to lots of tasty, calorie-rich insects.

I just can’t resist – ‘Would you like flies with that?’

So as you watch these magnificent birds fuel up on insects and gather in lines on the overhead wires, planning their incredible journey. Spare a thought and maybe say a little prayer for their safe flight south – and return next year.