Trends in rare breeding birds in the UK and the four countries

RBBP reports have, since 2015, presented trends for those species for which we believe annual coverage is sufficiently robust to do so. We do not present trends for species for which our reporting covers an insufficient proportion of the population, has significant geographical biases, or varies substantially between years (although we do present trends for such species if they are available from other sources such as periodic national surveys). In the species banners in the report we present trends for the most recent 25 years or the longest available period if we only hold data for fewer years (in 5-year blocks i.e. 10, 15 or 20 years). This year, with the addition of a new table in the report introduction, we have presented trends for these species over a greater range of time periods, both shorter and (if available) longer. All trends given except for those for the last year of change are derived from our long-standing approach of measuring change between 5-year rolling means; comparing the most recent mean (for 2020-24) with those from 10 years prior (2010-14), 25 years (1995-1999), and the longest possible period. The latter varies between species depending on when the RBBP began coverage (for those species on the RBBP list from the start it is 1973-1977), or when it began breeding in the UK. For colonising species the value of the trends reported are very sensitive to what start point is selected: we use the first year in which breeding was confirmed as the first year of the 5-year mean. Species are not included if the longest available trend is shorter than ten years. The 1-year of change figure is simply the change between the values for 2023 and 2024, without the ‘smoothing’ that the 5-year means provide. Thus, these values should be used and interpreted with caution, as for many species the change between single annual values is likely to arise, at least in part, from variation in recording and reporting effort (note that these are different things – not everything that is recorded by observers is reported to us!) rather than genuine change in its population. The smoothing process used for producing trends for longer periods helps to mitigate between-year fluctuations in recording and reporting, but the trends for any species for which reporting is incomplete may be subject to biases in effort and thus a degree of bias in trends.

As well as trends at the UK scale (with the ‘UK’ referring to the four countries of the UK (England, Wales, Scotland and Northern Ireland), plus the Isle of Man and the Channel Islands), we have also generated trends for each of the four countries for the species that occur in each country. The same considerations regarding trend quality apply; it may be that trends considered sufficiently robust for publication at a UK scale may not be consider so at the scale of one or more individual countries, or visa versa.

These tables are available as a pdf here.

¹figure in parentheses gives the absolute change in maximum total pairs between 2023 and 2024. ²length of trend is calculated between 5-year mean periods, e.g. 47 years between 5-year means for 1973-77 and 2020-24.

¹figure in parentheses gives the absolute change in maximum total pairs between 2023 and 2024. ²length of trend is calculated between 5-year mean periods, e.g. 47 years between 5-year means for 1973-77 and 2020-24.

¹figure in parentheses gives the absolute change in maximum total pairs between 2023 and 2024. ²length of trend is calculated between 5-year mean periods, e.g. 47 years between 5-year means for 1973-77 and 2020-24.

¹figure in parentheses gives the absolute change in maximum total pairs between 2023 and 2024. ²length of trend is calculated between 5-year mean periods, e.g. 47 years between 5-year means for 1973-77 and 2020-24.

¹figure in parentheses gives the absolute change in maximum total pairs between 2023 and 2024. ²length of trend is calculated between 5-year mean periods, e.g. 47 years between 5-year means for 1973-77 and 2020-24.