‘One swallow does not a summer make’ . . . But it is certainly a start and today (10 April) saw the first of these beautiful migrants swooping over the outskirts of Rhayader . . .
Although the cuckoo’s call is synonymous with late April, for most people the swallow’s excited bubbling torrent is every bit as evocative. This is not so much a song, but a cascade of notes, its flow punctuated with slight ticks as the blue-backed, brick-throated, fork tailed chorister flits low across lawns and fields.
Anyone with a resident pair of swallows will instantly recognise these calls as a concrete sign summer is on its way and it is a sound which we can all enjoy. The glossy-backed hordes are now flooding across the Channel, apparently completely fresh and invigorated by the 8,000-mile flight from their South African wintering grounds.
At first glance they can easily be confused with house- and sand martins, while the more distantly related swift also seems similar. A closer inspection reveals the swallow has a white belly which instantly rules out the all-black swift with its longer, scimitar-shaped, wings. House martins may share the white underside, but have an additional white stripe across their bottoms and lack the swallow’s ruby throat. Most characteristic of all, however, are the swallow’s long, deeply-forked, tails.
Although all three catch flying insects, their hunting behaviours also differ widely. Swifts generally fly highest and often hunt in shrieking packs that hurtle above streets and around buildings. House martins, on the other hand, typically swoop and dive around roof height. In contrast swallows tend to flit lower over meadows and lawns catching hovering insects just above the grass. These are snapped up in a surprisingly large mouth, smaller ones wrapped up into a glutinous food parcel, but larger ones delivered whole to the nest.
Location is another good indicator. Swifts usually rely on towns for nest sites – building these in cavities between the bricks of old houses and marking their return to the nest by hurtling between the houses in screaming gangs. House martins are as happy in a town as the country, provided they have a wide eave for their mud-and-spit nests.
Swallows are mainly rural birds, however, but almost invariably building their crude mud cup inside a building (the best way to encourage a pair is to leave a shed door or window open as careless gardeners can discover to their cost). This is a very recent development, for until 200 years ago they were cliff- and cave-dwellers. From here they adapted to the ledges beneath the tops of chimneys – but a century ago switched to an indoor life in barns, sheds or garages. This allowed them to dramatically increase their range and today they are predominately associated with the fields and meadows of traditional mixed farmland and village cricket pitches.
Swallows can often be communal, with several pairs nesting within the same building, but they are highly territorial with strong loyalties to a specific site. Parents and off-spring will return year after year to the same outbuilding and – if unexpectedly prevented from entering by conversion or repair – will spend pathetic hours searching for a way in.
Once they have found a site and built a nest, the female lays a clutch of four to five eggs which, incredibly, hatches in just over two weeks, with the young fledging a little under three weeks later. Although the parents continue to feed the young for another fortnight, they soon begin another cycle and this rapid turnover means each pair can rear up to 15 young in a summer. To fuel this requires Herculean efforts, with the parents returning to the nest every few minutes, their beaks bursting with insects.
It is thus unsurprising that at the summer’s end they suddenly appear to lose interest in nesting and instead they gather in excited gangs on telephone wires. The melodious breeding babble is now replaced by excited twittering as they summon up the energy for their long journey south. Then, one day in late September, they are gone and their air falls silent until one day in early April when the vanguard returns, fresh for the fray.