England Biodiversity Strategy Indicators

On March 20th 2006 the government released the updated wild bird indicators for England and the English Government Office Regions. These were produced for Defra by the BTO and the RSPB drawing on their extensive range of survey data.

There are five landscape themes in the England Biodiversity Strategy Indicators (Farmland, Woodland, Wetland, Urban and Coastal) and indicators have been produced for each, as well as an all species indicator. The indicators span different time scales of between 10 and 34 years depending on data availability. Populations of common birds are thought to be a good indicator of the state of the environment as they occupy a wide range of habitats, tend to be near the top of the food chain and long-term data are available to assess population changes.

Farmland Bird Indicator

The farmland bird indicator runs from 1970 and includes 19 species. The data used to compile the farmland bird indicator were from the Common Bird Census (CBC) and the BTO/JNCC/RSPB Breeding Bird Survey (BBS). There was a significant decline in farmland birds in the late 1970s and throughout the 1980s which has now stabilised but numbers of farmland birds remain at low levels of approximately 50% of 1970 numbers. The decline in farmland birds appears to have been driven by a decline in farmland specialists, while farmland generalist species have remained at fairly stable levels since 1970. The farmland bird indicator has been adopted as a Public Service Agreement target, with a commitment to reverse the decline in farmland birds by 2020.

Figure 1. Indicator of farmland bird populations 1970-2004

Woodland Bird Indicator

The woodland bird indicator also runs from 1970 and includes 33 species. The data used to compile the woodland bird indicator were from the CBC and BBS. There was a significant decline in woodland birds in the late 1980s and early 1990s. As with the farmland bird indicator this decline seems to have halted and woodland bird numbers have stabilised at about 85% of 1970 numbers. This decline in the woodland bird indicator is due to woodland specialists declining to approximately 70% of the 1970 levels as woodland generalists have remained at approximately the same level as in 1970.

Figure 2. Indicator of woodland bird populations 1970-2004

Water and Wetland Bird Indicator

The water and wetland bird indicator runs from 1975 and includes 21 species, which are split into fast water species (3), Slow/still water species (14) and wet meadow species (4). This indicator has varied quite markedly, but has been relatively stable over the past seven years and is now at about 11% below its 1975 starting point. This graph highlights the worrying decline in some species characteristic of wet meadows. The data used to compile this indicator was from the Waterways Bird Survey (WBS), Rare Breeding Birds Panel, Heronries Census and from joint modelling of data from the CBC and the BBS.

Figure 3. Indicator of water and wetland bird populations 1975-2004

Town and Garden Bird Indicator

Two versions of the town and garden bird indicator are presented here. One, which runs from 1994 and is based on 27 species monitored by the BBS, shows that breeding populations of these characteristic species of towns and gardens have increased by 11% in England since 1994, although the populations of 4 species classified as urban specialists are 14% below their 1994 levels. The other version shows changes in numbers of birds in gardens in late winter and early spring since 1995 (based on 23 species monitored by the BTO Garden Bird Watch Survey). Fluctuations in this index are likely to reflect the winter weather severity.

Figure 4. BBS indicator of town and garden bird populations 1994-2004

Figure 5. Garden Bird Watch indicator of town and garden bird populations 1995-2004

Coastal and Sea Bird Indicator

The coastal and sea bird indicator runs from 1986 and includes 9 species, which are split into surface piscivores (5) and sub-surface piscivores (3). The data used to compile the coastal indicator are from JNCC’s Seabird Monitoring Programme (SMP) and RSPB tern monitoring. The overall coastal indicator is at approximately the same level as the 1985 start point, although the surface piscivores have declined by nearly 20% and the sub-surface piscivores have increased by nearly 50% over this time period.

Figure 6. Indicator of coastal and sea bird populations 1986-2004

All Species Indicator

The all species indicator runs from 1970 and includes 96 species of common native breeding birds for which reliable, long-term data are available for England, predominantly from the CBC and BBS. This indicator has fluctuated since 1970 with a peak in the mid 1970s followed by a decline in the 1980s and 1990s and then recovering slightly to approximately the same level as the 1970 start point.

Figure 7. Indicator of all common, native bird populations 1970-2004

Increases in a wide range of species have counteracted the effect of the significant declines in farmland and woodland birds. The other three indicators have shown healthier trends, being either at a similar level to their start point (coastal indicator), or only slightly up (urban indicator) or down (wetland indicator) on their start points. However, within each group there are species, or groups of species, for which there is concern and all of these indicators include species that have shown large declines.

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