The cuckoo, the bird whose two-note call has long been one of the iconic sounds of spring, has been added to the Red List of Britain's most threatened species.
Once familiar everywhere in the countryside, the cuckoo has declined by 60 per cent in the last forty years, and by 40 per cent just since 1994, and has now vanished from many parts of Britain, especially in the south.
It is one of a suite of birds which migrate to Britain from wintering grounds in central Africa south of the Sahara desert, all of which are showing sharp falls in numbers. Some of these, such as the turtle dove and the spotted flycatcher, are already on the Red List; now four more trans-Saharan migrants, the wood warbler, the yellow wagtail, the tree pipit and the golden oriole, join the cuckoo on the list for the first time.
The Red List represents the most threatened category of the Birds of Conservation Concern assessment, which is produced every few years by a partnership of Britain's bird protection groups and the statutory conservation agencies. The new assessment, Birds of Conservation Concern 3, is the first revision since 2002 of the Red, Amber and Green Lists into which Britain's 246 regularly-occurring bird species are divided, according to the perceived threats to their conservation status. Birds are generally put on the Red List if they have experienced at least a halving of their historic populations. Alarmingly, red-listed species, now 52, account for more than one in five (21 per cent) of all the total, and represent a far higher proportion than compared to the last assessment, when 40 species (16 per cent) were red listed.
Besides the cuckoo and its fellow summer visitors, the 18 species red-listed for the first time such familiar birds as the lapwing and the herring gull, uncommon woodland species such as the hawfinch and the lesser redpoll, and two Scandinavian thrushes which visit Britain commonly in winter but breed in small numbers in Scotland, the fieldfare and the redwing.
Also newly on the list are a number of seabirds and waders, including the arctic skua, the Balearic shearwater, Temminck's stint, the ruff and the whimbrel, and two winter visitors whose numbers have dropped sharply, the dunlin, a small wader, and the scaup, an Arctic-breeding duck. But the most eye-catching addition is that of the cuckoo – famous for laying it eggs in other birds' nests as well as for its call – and the other summer visitors.
"The dramatic decline of the cuckoo is extremely worrying," said RSPB conservation spokesman Grahame Madge. "For millennia, this bird has been the harbinger of spring, but now its population crash is proclaiming that it and many other summer visitors are in deep trouble.
"The cuckoo is one of our most widespread birds, occurring in almost every open habitat from the Cornish valleys to the Scottish Highlands, so it is puzzling why such an adaptable bird should be declining so rapidly.
"Our scientists will be looking for answers to this problem. But to research this bird we will have to look at all aspects of its behaviour and at both ends of its trans-Saharan migration. Although the cuckoo is much a part of an English summer as village cricket or a cream tea, it really is an African bird that comes here to lay its eggs, so we'll also have to research the cuckoo on the Kenya savannahs as well as the orchards of Kent."
The Red List of British birds represents a parallel but different assessment from the global red lists produced by the International Union for the Conservation of Nature (IUCN), which feature species threatened with world extinction. The Birds of Conservation Concern Assessment deals with birds in a purely British context.
It is a produced by a partnership of the RSPB with the British Trust for Ornithology, the Countryside Council for Wales, the Game & Wildlife Conservation Trust, the Joint Nature Conservation Committee, Natural England, the Northern Ireland Environment Agency, Scottish Natural Heritage, and the Wildfowl & Wetlands Trust.
The 2009 assessment does contain some good news. Six species (stone-curlew, woodlark, quail, Scottish crossbill, bullfinch and reed bunting) have been removed from the 2002 Red List, largely because of a recovery in their numbers or range, or a better understanding of their populations. These species are now placed on the Amber List.
Red List: Birds in danger
Large, colourful thrushes, they stand very upright. They are very social birds, spending the winter in flocks of anything from a dozen or two to several hundred.
A secretive bird which keeps to the high tree canopy, it can be heard, most often at dawn, giving its distinctive fluting whistle. The male has an unmistakable bright yellow body with black wings.
Also known as the peewit in imitation of its display calls. This familiar farmland bird has suffered significant declines in the last 25 years.
A diving duck with a resemblance to tufted duck. Males have black heads, shoulder and breast, grey back and a black tail. Females are brown, with characteristic white patches around the base of the bill.
The attractive but unobtrusive wood warbler is the largest Phylloscopus warbler in Europe. It has bright yellow upper parts, throat and upper chest and white under parts.
A yellow and green bird, with a medium-length tail, and slender black legs. It spends much time walking or running on the ground.