There is a sense of anticipation in our household at the moment, for any day now will see the return of our breeding swifts. This is the first house that I have shared with swifts and their presence during the early part of the summer is one of the perks of urban living. To sit in the back garden on a still summer’s evening and watch the parties of swifts screech past is magical. No wonder Ted Hughes felt driven to write a poem about them – these birds are the true masters of our skies.
The first swifts have been in the country for a couple of weeks now but the main arrival comes at the start of May, with birds returning to nest sites used the previous year. Their stay is a brief one, just sixteen weeks, making them one of the last migrants to arrive in spring and first to depart in late summer. The largest colonies within the county can be found in Norwich, where the birds nest in cavities under the eaves of older properties. Many of these nesting sites have been lost over the years as renovations restrict access to nesting chambers. New properties tend not to be swift-friendly, although some local authorities have taken the lead in adding swift boxes to their new developments, something that is not only an encouraging sign but also an indication of the strength of the relationship between ourselves and these enigmatic visitors. The name ‘swift’ comes from the Old English word ‘swifan’ which means ‘fast moving’, an apt name for this slender-bodied bird with its long, swept-back wings. Edward Thomas, in his poem ‘Haymaking’, described their form ‘as if the bow had flown off with the arrow’ and to me, this seems a most fitting description.
Swifts feed at higher altitudes than either swallows or house martins and undertake long flights in search of food. Depending upon the weather systems in place at the time, swifts breeding in Britain may forage as far afield as Germany, tracking clockwise around low-pressure systems to seek out areas with the greatest abundance of prey. If weather conditions are poor, then adult swifts may be unable to find sufficient food for their chicks and the chicks will enter a state of torpor. This behaviour enables them to go without food for up to 48 hours. Immatures may not breed until their fourth year and it is thought that during this period they remain entirely on the wing, again highlighting their mastery of the air. Given this behaviour, and the short duration of their stay in Britain, we cannot really call them ‘our’ swifts. They are brief visitors and we should enjoy them while we can.