A flash of cobalt across a farmyard, accompanied by a burst of enthusiastic twittering, can only mean one thing: the swallows are back from South Africa. The first sight and sound of a swallow dispels winter blues at a stroke.
April is the month in which to celebrate migration. While the flocks of winter ducks, geese and waders wing their way north, the African migrants pour in from the south. It’s a time for relearning plumages, calls and songs as we re-acquaint ourselves with birds we haven’t seen for six months or more. All our smaller green migrants are insectivores and their arrival coincides with the emergence of insects across Europe. Queen bumblebees, roused from hiber- nation, drone past, searching for nest-holes. Caterpillars swarm over unfurling leaves.
The real excitement this month is seeing birds that may not breed in your neighbourhood passing through en route to their nesting areas. For the dedicated patch-watcher – and your patch may be your garden, local park or a chink of conveniently placed countryside – April can bring all kinds of dividends, whether flying yellow wagtails betraying themselves with a loud “wheesp”, redstarts along a woodland edge, northern wheatears landing on the local playing fields or a swallow, back on the wire and singing in the hope of attracting a mate.
We now know this may be the very same bird that was here last summer and although the lively twitters we hear in April are technically about establishing a territory, it’s hard not to think of them as a celebration of a homecoming, and marking the true arrival of spring.
Strung out like musical notes on a stave, swallows are twittering as they gather on telegraph wires. Adult swallows are one of the smartest and most elegant birds, with a long, forked tail, shining blue back and wings, and a brick-coloured throat patch. Some males have tail-streamers longer than their peers, and we now know that female swallows find this attractive and are more likely to mate with long- tailed suitors.
Sometimes you may see a single swallow land on a wire and begin twittering. Within a minute or two, a second has arrived, then another, until dozens have congregated.
But these aren’t necessarily local birds: they often include swallows that have bred in Scandinavia, mingling with our birds before embarking upon that incredible autumn voyage over the Mediterranean and Sahara Desert, then down to the very tip of Africa.
On a misty April morning, as a light breeze rustles the tops of last year’s reeds, you might hear one of the most peculiar sounds in nature: a deep, lowing call more like a distant foghorn than a bird. This is the famous boom of one of our rarest and most elusive breeding birds: the bittern. Its boom is lower-pitched than any other UK bird, and also carries further: as much as 5km when the air is still.
You are far more likely to hear a bittern than see it, for this relative of the familiar grey heron prefers to spend its time deep in the heart of reed beds. Its cryptic plumage, streaked dark and light brown like the reeds themselves, makes it very hard to see, especially if it adopts its characteristic pose of standing stock-still with its beak pointing vertically upwards.
Over the past two centuries or so, bittern numbers have declined severely with the drainage of their wetland homes. They became extinct as breeding birds in Britain by the year 1900, though they soon returned to nest in small numbers, mostly in East Anglia. But the efforts of conservationists determined to save this unique bird have paid off: there are now well over a hundred booming male bitterns in Britain, with more than 30 at just one site, the Avalon Marches in Somerset.
As you walk through a wood, the strengthening breeze and greying skies suggest that fickle April is sending showers your way. Before the raindrops start to fall, you will sometimes hear a loud, laughing call: a green woodpecker.
This maniacal sound gave the green woodpecker its old country name of “yaffle”, and it may not be pure coincidence that you hear one before a shower. Another folk name for our largest woodpecker is “rain bird”, as it is supposed to herald the onset of showers.
It’s a sound you hear in woods, parks, heaths and large gardens throughout most of Britain, though not in Ireland, as the Irish Sea proved too much of a barrier for these birds as they headed north and west after the end of the last Ice Age. You might expect to find woodpeckers in trees; although green woodpeckers do nest there, they spend far more time on the ground, probing lawns and meadows for their main food: ants and their pupae.
As you watch from a clifftop, the movement of a bird catches your eye. At first it looks like just another gull, but as it turns in mid-air, something about its stiff-winged flight action makes you realise this is different – a snow-white bird with grey wings, a dark smudge around the eye and a short, stubbly bill: not a gull at all, but a fulmar. You can’t help but admire fulmars as they soar and wheel around vertiginous cliffs. Eventually, one settles to greet its mate with a chorus of cackles like a manic witch.
In the Victorian era, fulmars were rare in Britain, confined to the remote archipelagos of St Kilda and Shetland. But over the following century the fulmar expanded its range more than any other native breeding bird, colonising virtually the whole of the British and Irish coastline. Their success means we can now all enjoy the sight and sound of a colony of fulmars gliding and wheeling over a clifftop in spring.