Dear Ian

Wild bird populations in England and the UK

Thank you for inviting us to review your Wild bird populations in England and Wild bird populations in the UK statistics against the Code of Practice for Statistics, alongside our review of Butterflies in England and Butterflies in the UK statistics.

These are a valuable set of statistics as bird populations are considered to provide a good indication of the broad state of wildlife in the UK, with the trends in bird populations used by policy makers, government agencies and non-governmental organisations. Our review found the statistics are presented impartially and objectively within the statistical bulletin. Helpful insights are provided throughout the bulletin on the movements in the data for the bird species, and appropriate warnings are provided about not relying too much on the short-term trends as the indices are considered to give reliable medium to long-term trends.

We welcome that the statistics are being developed further through the introduction of a new experimental statistic for an upland bird indicator and that the statistics team is actively seeking user feedback on this. We look forward to decisions made about this new indicator being transparently communicated to users.

The bulletin is supported by a comprehensive Technical report containing information on the data sources and methods used, which helps users understand them. The additional FAQ and Brief Introduction to the Wild Birds Populations Indicator documents are very informative, setting out the information at a level that makes it easier for users to understand, and we encourage the statistics team to better promote this material to help utilise its value.

We welcome that the team is in the process of formalising a user engagement strategy and we have several resources available for the team to draw on to engage a wider range of users such as our user engagement guidance which provides a useful framework to help plan these activities. This wider engagement can help inform any future decisions regarding these statistics that will help to ensure that they remain useful, relevant and continue to support understanding of this important area. The Government Analysis Function is also developing a User Support and Engagement Resource (USER) hub which contains helpful guidance on engaging with users.

Your team told us that the strong relationship with the expert organisations providing the data enables constructive conversations about the data and their quality. While the quality assurance processes carried out by the data collectors is set out in detail in the technical report there is no published information about any of the statistics team’s own quality assurance. To help support appropriate use of the statistics and further assure users of their quality, information should be added on the strengths and limitations of the data and what quality assurance processes the data go through once received by the statistics team.

We found that it is not clear from the published material that annual revisions to the time series data occur solely due to the smoothing process used (unless an error in the data is identified after publication). This should be made clearer to users to help their interpretation of the trends over time.

The trustworthiness of government statistics is in part determined by them being known to be produced independently from outside influence and this perception can be brought into question when pre-release access is too wide. Given this, we recommend that the list of individuals granted pre-release access for this set of statistics should be reduced substantially.

There are similarities in the nature of the data used and the statistics provided on butterflies and birds. We would strongly recommend the team consider the assessment findings and associated requirements as they relate to these Wild Bird statistics.

Our Transport, Environment and Climate Change domain lead will continue to engage with you and your team on progress in the coming months. Please do not hesitate to get in touch if you would like to discuss any aspects of this letter further.

Yours sincerely


Mark Pont