Lord of the Skies

.... when swifts want to go to sleep, they go higher and higher in the air until they become invisible to the naked eye.  They then cruise around at high altitude taking short ‘cat naps’....

If you want to marvel at how incredible wildlife can be you only have to look at the swift. This wonderful bird epitomises how creatures adapt to the world they live in and exploits any advantage they can that provide opportunities for them to survive in a competitive, crowded and increasingly hostile environment.

Most of you have seen a swift even if you are not aware that you have. Their screeching calls as they scythe through the towns and villages of Sussex is one of the sounds of summer; as much part of our aural landscape as is the gentle knock of leather against willow, the buzzing of bees, the whine of electric lawnmowers and the sizzling of burnt sausages on the barbecue. 

If you are not sure what they look like, turn your gaze upwards on a warm summer evening and you may well see what resembles a small flying anchor darting round the rooftops at great speed. Essentially they are all wing; the wingspan reaches 40cms (16ins) which is over twice the length of the body. They are essentially designed for life in the air and this leads to the first remarkable fact about swifts.

Once they leave the nest a swift spends the next three years of its life in the air; never landing anywhere. In this time it migrates back and forth to Africa no less than six times; it eats, rests and eventually in its fourth year, mates on the wing. If they could devise away of building a nest and raising young on the wing they would have done so by now. Swifts have evolved to a degree that there legs are now unnecessary and to all intents and purposes useless; if they fall to the ground they have no muscle power at all so are not able to push up to launch themselves into the air and would undoubtedly perish.

Having to breed and raise young means finding a surface on which to lay eggs at a height that, when they the young are ready to leave the nest they are high enough up to launch straight into an up current. Two eggs are usually laid on a flat piece of wood or concrete under eaves or even tiles where there is a small enough gap for these ultra slim birds to squeeze into. That’s why church towers and older, tall buildings with plenty of gaps are ideal for these originally cliff nesting birds, while today’s buildings are far less suitable being that we are now concerned more with clean designs and no gaps to let wildlife in.

Another remarkable fact is that when swifts want to go to sleep, they go higher and higher in the air until they become invisible to the naked eye.  They then cruise around at high altitude taking short ‘cat naps’ until it is warm enough to start feeding again. Feeding is all done in the air with the birds able to collect up to 400 insects in one ball as they are able to extend their gape like a net, catching the their prey at great speed. Another fascinating facts is they are quite capable of travelling hundreds of miles in a day to find food should the weather be cold in their breeding grounds and it is quite feasible that Sussex  based swifts will fly to central France and back in a day should they need to.

Swifts are one of the last of our migrant bird species to arrive back in the UK from Africa and we usually don’t see them until the beginning of May.  Their time here is pretty short - just enough to raise a brood so that by mid-August they have nearly all embarked on their journey back south.

Sadly swift numbers are declining in the south east of England, mainly due to a fall in the number of insects and a loss of breeding sites. Around Sussex, concerned swift lovers have put up specially designed nest boxes for them with some degree of success and it is hoped that this will help reverse the fall in numbers of this enigmatic and wonderful Lord of the Skies.

Mike Russell
Sussex Wildlife Trust 
www.sussexwt.org.uk

Return To News Page