The Great Arrival

More than one author has conjured up the image of a Great Arrival, the 16 million or so migrant birds all heading north to summer on these northern breeding grounds. Most recently, in his excellent book Say Goodbye to the Cuckoo, Michael McCarthy speculated on how we would react were all these birds to arrive in a single flock. Such a flock would fill the sky; people would stop what they were doing in order to take in the spectacle and it would become an important signal that spring had reached our shores, celebrated with street parties and a public holiday.

Of course, our summer migrants do not arrive all at once in some grand flock; instead they turn up in small numbers or individually, with many arriving at night when the energetics of migration are better balanced. These overnight arrivals do provide one thing however; they deliver a sense of the unexpected to us birdwatchers, the thrill that the night just gone might have delivered some exciting find to an early morning trip to a patch of coastal scrub or waterside reedbed. Even those who would not describe themselves as a birdwatcher derive a thrill from seeing the summer’s first Swallow or hearing May’s first Cuckoo.

While these individual encounters act in some small way as a talisman for a wider arrival, the movement of this mass of birds, streaming out of Africa and up across Europe, goes largely unnoticed. Taken for granted, we find ourselves unaware of the problems faced by these many and varied travellers, problems which have resulted in dramatic population decline for some species. We only know of the changing fortunes of our summer visitors because of the work of organisations like the British Trust for Ornithology (BTO), whose partnership between researchers and birdwatchers provides regular monitoring of the birds breeding across Britain and Ireland. Yet even with this information we only know that something is wrong, we don’t fully know why. Are the numbers of Wheatears, Cuckoos, Turtle Doves and flycatchers falling because of difficulties here or is it because of problems on their wintering grounds or along their migration routes?

Recently, the BTO and RSPB have launched projects in Africa to look at our migrants on their wintering grounds, seeking to understand what is happening to the habitats they use during our winter. This work is only the start of a wider process which, ultimately, will need to feed into conservation action targeted at the different species across their whole range. The scale of this work also serves to bring home the message that while we view these birds as being ‘ours’, they are only ours for part of the year.

Lament of the summer crooner

Over the last two weeks, my early morning walks through the forest have been accompanied by the gentle purring call of a turtle dove.  This, our only migrant member of the pigeon family, is a summer visitor to Norfolk, arriving in late April or early May. By now, many pairs will have laid their first clutches of eggs and may just, if conditions are favourable, produce another before departure to their African wintering quarters. For me, the soft hypnotic purr is a reassuring part of summer, heard in my youth from southern counties on warm summer evenings and now a feature of my morning walks. Yet, there is a sorrowful undertone to the call itself, something that has resonance with many who hear it. Shakespeare famously used the image of a calling turtle dove in the final scene of The Winter’s Tale, when Paulina proclaims “I, an old turtle, will wing me to some whither’d bough, and there my mate, that’s never to be found again, lament till I am lost.”

The turtle dove has a breeding range that is largely restricted, within Britain, to the southeast of England. This reflects an association with arable land, the birds favouring areas with suitable thick hedgerows for nesting and abundant weed and (latterly) cereal seeds for food. Historically, it was believed that the arable weed fumitory was the most important food item but recent work by the Game Conservancy, carried out here in East Anglia, has shown that oilseed rape and cereal now dominate. Perhaps the increasing use of herbicides to control arable weeds has forced the birds to exploit new feeding opportunities. Other evidence also points towards the birds finding it more difficult to survive within a changed arable landscape. Individuals will travel up to 10km from their breeding territories in order to find good feeding opportunities and this, coupled with a decline in nest site availability, may be behind an 80% decline in numbers between 1967 and 1999.

It is not just within Britain that the turtle dove population has been under pressure. The wintering areas in Sahelian Africa have increasingly suffered from drought and the birds themselves are heavily persecuted during migration by hunters. Within France, where such hunting is illegal under European legislation, nearly 200,000 were shot in Autumn 1998, while a further 25,000 were shot on their return northwards the following spring.  For a species that is now having difficulty in rearing more than one brood in a season, such levels of persecution cannot be sustained. Against such a background, Shakespeare’s verse takes on a different meaning. The day may soon come when we lament the passing of the turtle dove’s song from our summer overture.