Headline indicators for sustainable development: populations of wild birds in the UK, 1970-2005

The government’s Quality of Life Wild Bird Indicators, first published in 1999, are updated annually in a joint project between Defra, BTO and RSPB. They were developed to give a broad summary of the general health of wildlife in the general countryside. Birds are regarded as good general indicators of this as they are wide ranging in habitat distribution and tend to be at or near the top of the food chain (Furness & Greenwood 1993). The indicators show changes in the populations of common native species of farmland and woodland birds, as well as a summary indicator, which includes information for other UK bird species. Data on population trends for the species in the indicator come from a variety of sources, most notably the BTO/JNCC/RSPB Breeding Bird Survey. This is the update of the QOL wild bird indicators from 1970 to 2005.

All species indicator

The all-species line, which includes the population trends of 113 species from a wide range of habitats (coastal, wetland, upland and urban as well as farmland and woodland) went up by 2% of its 2004 value to reach an index 10% higher than its value at the starting point in 1970, continuing the steady increase evident since the early-1990s. Declining species include many long-distance migrants, such as Tree Pipit, Yellow Wagtail, Sedge Warbler, Lesser Whitethroat and Redstart. Species contributing to the current positive trend include some of the scarcer species in the indicator, such as Capercaillie, Corncrake and Cirl Bunting, which have been recipients of targeted conservation action, as well as more common species such as Jackdaw and Great Spotted Woodpecker.

Within the long-term stability shown by the all-species indicator there is considerable variation in the trends shown by different groups of species, with the most obvious being the declines shown by birds of farmland and of woodland. The two habitat-specific indicators for woodland and farmland illustrate the long-term declines of birds of these habitats, being respectively at 91% and 56% of their 1970 starting values; both have shown a very slight decrease since last year.

There is a new seabird indicator this year, which is a modified version of the coastal species indicator, used in previous years, and includes two new species, Black Guillemot and Razorbill. Eider and Shelduck are no longer included in this indicator but are still included in the all species indicator. The indicator increased steadily throughout the 1970s and 1980s, to a high point of 38% above the 1970 level in 1989. However, in recent years there have been alarming declines in some of the contributing species, such as Kittiwakes, Shags and Fulmars, contributing to a decrease in the indicator to 32% above the 1970 starting point.

Woodland species indicator

Woodland indicator species:

Specialists:
Blackcap, Chiffchaff, Coal Tit, Garden Warbler, Goldcrest, Great Spotted Woodpecker, Hawfinch, Jay, Lesser Spotted Woodpecker, Marsh Tit, Nightingale, Nuthatch, Redpoll, Redstart, Sparrowhawk, Spotted Flycatcher, Tree Pipit, Treecreeper, Willow Tit, Willow Warbler

Generalists:
Blackbird, Blue Tit, Bullfinch, Chaffinch, Dunnock, Great Tit, Green Woodpecker, Lesser Whitethroat, Long-tailed Tit, Robin, Song Thrush, Tawny Owl, Wren.

The woodland indicator increased by 4% between 2004 and 2005 to its highest level since 1990, although still only 91% of the 1970 starting level. The indicators for both the woodland generalists and specialists have increased between 2004 and 2005, by approximately 8% and 2% respectively, although the specialists are still down at 81% of their 1970 level. The increase in the generalists indicator is driven by increases in abundant species such as Great Tit and Wren, as well as the welcome increase in species such as Bullfinch, which is recovering from a historical decline between 1970 and the late 1990s. The woodland specialist indicator increase is driven by increases in species such as Great Spotted Woodpecker, Sparrowhawk, Nuthatch and Blackcap, which have all more than doubled since 1970. However, Lesser Redpoll, Willow Tit, Spotted Flycatcher and Lesser Spotted Woodpecker have decreased to less than a quarter of their 1970 levels.

Farmland species indicator

Farmland indicator species:

Specialists:
Corn Bunting, Goldfinch, Grey Partridge, Lapwing, Linnet, Skylark, Starling, Stock Dove, Tree Sparrow, Turtle Dove, Whitethroat, Yellowhammer

Generalists:
Greenfinch, Jackdaw, Kestrel, Reed Bunting, Rook, Wood Pigeon, Yellow Wagtail.

The farmland bird indicator was virtually stable between 2004 and 2005 (it showed a 0.1% decrease from the value for 2004), and remains at just 56% of its 1970 level. The indicator for farmland generalists increased by 6%, with all seven species, except for Rook and Yellow Wagtail (which is now at only 34% of its 1970 level), showing an increase since 2004, and Jackdaw and Woodpigeon numbers are more than double 1970 levels. The farmland specialist indicator, however, declined by 1% in 2005 to the lowest it has ever been, 38% of its 1970 level. Eight of the 12 specialist species have declined over the last five years, with Tree Sparrow, Corn Bunting, Grey Partridge and Turtle Dove all at less than 20% of their 1970 levels.

Wintering waterbird species indicator

Wintering waterbird indicator species:

Wildfowl and allies:
Bewick’s Swan, Coot, Cormorant, Dark-bellied Brent Goose, European White-Fronted Goose, Gadwall, Goldeneye, Goosander, Great Crested Grebe, Icelandic Greylag Goose, Light-bellied Brent Goose (High Arctic), Light-bellied Brent Goose (Svalbard), Little Grebe, Mallard, Mute Swan, Pink-footed Goose, Pintail, Pochard, Re-established Greylag Goose, Red-brested Merganser, Shelduck, Shoveler, Svalbard Barnacle Goose, Teal, Tufted Duck, Whooper Swan, Wigeon.

Wader species:
Avocet, Bar-tailed Godwit, Black-tailed Godwit, Curlew, Dunlin, Grey Plover, Knot, Oystercatcher, Redshank, Ringed Plover, Sanderling, Turnstone.

The wintering waterbird indicator has increased by 114% since the baseline season of 1974/1975 with a recent decline of 13% between 2003/04 and 2004/05. The two subsets of wader species and wildfowl and allies that make up the wintering waterbird indicator both show a similar pattern. Wader species have increased by 67% since 1974/1975, despite a slight decline (10%) in the last year, with Avocet and Black-tailed Godwit having shown the largest increases. Wildfowl and allies have increased by 145% since 1974/1975, with a decline of 15% in the last year. Re-established Greylag Goose and Gadwall are two wildfowl species that have particularly increased since the start of this indicator. Only seven species that contribute to the wintering waterbirds indicator have decreased since 1974/1975. Of these, Pochard and Dunlin show the steepest declines, 41% and 38% respectively.

Methods

The trend information, for the all species, farmland and woodland indicators, is mainly obtained from the BTO’s Common Birds Census, which ran from 1962 to 2000 (see Wider Countryside Report), and the BTO/JNCC/RSPB Breeding Bird Survey, which began in 1994 (see BBS). The trend information for the wintering waterbird indicator is mainly obtained from the Wetland Bird Survey (WeBS), which is jointly run by BTO, WWT, RSPB and JNCC. The indicator value for each year is the geometric mean of the constituent species' trends. Within this multi-species index, each species is given equal weighting, regardless of population size or conservation status. Individual species populations within the index may be increasing or decreasing, irrespective of the overall indicator trends. For further details on trend information, see Wider Countryside Report.

Reference:
Furness, R.W. & Greenwood, J.J.D. 1993. Birds as monitors of environmental change. London: Chapman & Hall.

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