Wild Bird Indices: tracking trends in the condition of habitats

Ben Lascelles Eurasian Curlew are declining mainly as a result of agricultural intensification. Zoom In | Hi-Res

Bird populations are a good indicator of overall environmental sustainability. BirdLife are developing indicators based on the population trends of bird species selected to be representative of particular habitats in order to track trends in the condition of these habitats.

• Wild Bird Indices show the average trends in abundance of a selected set of species. They are especially useful in showing change in the overall condition of ecosystems, which is difficult and expensive to measure directly.
• Using birds has many advantages: excellent data, based on the volunteer efforts of skilled birdwatchers; a stable taxonomy; a thorough knowledge of ecology and behaviour; meaningful responses to environmental change, and great resonance and symbolic value with the public and decision-makers.
• Bird populations integrate a set of environmental changes, because they are mobile and often wide-ranging. Bird numbers also respond more slowly than those of smaller organisms, and at a larger spatial scale.
• Strengths of common bird indicators include their statistical robustness, relative simplicity, cost-effectiveness and ease of update.
• Wild Bird Indices can help measure progress towards reducing the rate of biodiversity loss at the national, regional and global levels.

A national example: the UK common bird indicator

• This indicator is based on population trends of common breeding birds.
• It is one of the UK Government's 15 headline indicators of the sustainability of lifestyles in the UK.
• It shows large declines in common woodland and especially farmland birds since 1970.
• The UK Government has adopted a formal commitment to "reverse the long-term decline in the number of farmland birds by 2020".
• UK land-use policy is now coupling agricultural production with the needs of maintaining and restoring biodiversity.

The UK common bird indicator

A regional example: the Pan-European common bird indicator

• This indicator has been developed by BirdLife International, the European Bird Census Council, RSPB, and Statistic Netherlands. It shows average trends in population sizes of a suite of common breeding birds across 18 European countries.
• It is based on national annual breeding bird surveys conducted by skilled volunteers.
• It shows that common farmland birds in Europe have declined steeply over the last two decades, common woodland birds have declined moderately, whilst common generalist species have increased.
• The European Union has adopted the farmland bird index as a "long-list structural indicator" for Europe.
• Read the State of the World's Birds case study.

The Pan-European common bird indicator

GLOBAL: Scaling up common bird indicators

• Similar analyses are underway to produce Wild Bird Indices for North America based on the Breeding Bird Survey.
• New bird population monitoring schemes are being initiated in a number of countries, with the African region piloting this approach (download Global Wild Bird Indicator leaflet; PDF 325KB). These will produce data to allow national indices to be produced, and to contribute to a global Wild Bird Index in due course.
• Indicators are under development for species groups that have been counted in many countries for many years, such as waterbirds (led by Wetlands International), seabirds and birds of prey.
• Thousands of birdwatchers around the world make bird lists, which may be capable of providing a reliable index of species abundance changes. Such lists are now being captured through web-based systems in a number of countries (see www.worldbirds.org) and research is underway to test how these data might feed into a global Wild Bird Index.

The development of global Wild Bird Indices is supported by the 2010 Biodiversity Indicators Partnership

Related Links

• Gregory et al. (2005) Developing indicators for European birds paper in Phil. Trans. Royal Soc 360, 269–288. (PDF, 339KB)
• Global Wild Bird Index leaflet (PDF, 325KB)
• A Biodiversity Indicator for Europe: Wild Bird Indicator Update 2005 (PDF, 277KB)
• Common bird indicators: helping to track progress towards the 2010 target - leaflet (PDF, 116KB)
• Common bird indicators: helping to track progress towards the 2010 target - poster (PDF, 567KB)
• Global Wild Bird Index Factsheet