This spreadsheet is the underlying data for the biodiversity indicator C5, Birds of the wider countryside and at sea.
Bird populations have long been considered to provide a good indication of the broad state of wildlife. Birds occupy a wide range of habitats and there are considerable long-term data on changes in bird populations, which help in the interpretation of shorter-term fluctuations in numbers. As they are a well-studied taxonomic group, drivers of change for birds are better understood than for other species groups, which allows for better interpretation of any observed changes. Birds also have huge cultural importance and are highly valued as a part of the UKâs natural environment by the general public.
The indicator shows changes in the breeding population sizes of common native birds of farmland and woodland and of freshwater and marine habitats in the UK.
The indices show the year-to-year fluctuation in populations, reflecting the observed changes in the survey results, and smoothed trends, which are used with their confidence intervals to formally assess the statistical significance of change over time. Smoothed trends reduce short-term peaks and troughs resulting from, for example, year-to-year weather and sampling variations.
This is one of a suite of 24 UK biodiversity indicators published by JNCC on behalf of Defra; the latest publication date was 19 January 2016 - for indicator C5 the latest data are for 2014. The supporting technical document details the methodology used to create the indicator.