The SEO/BirdLife report correctly summarizes the poor conservation status of waterbirds in Doñana, especially based on censuses carried out by the EBD-CSIC between 2004 and 2022. It also identifies the main threats and proposes a series of management measures that would help improve the situation.  

Waterbirds serve as bioindicators for aquatic biodiversity in general. Their main advantages are that they are easy to count compared to other animals (such as fish, amphibians or invertebrates) and that there are historical data that allow us to understand the changes in Doñana from decades or even a century ago. Some of the threatened species were much more abundant in Doñana a century ago than in any year studied in the report (e.g., marbled teal or brown pochard). The negative trends in populations of many species since 2004 demonstrated in this report reflect, above all, the deterioration in water quantity and quality in the Doñana marsh. 

However, most birds are migratory and trends also depend on changes along their migratory routes, so it is always best to contrast trends in Doñana with those recorded in the rest of Europe, something that is not done in the report. Likewise, possible changes in the distribution of species due to their thermal niches, following the increase in temperatures that have already been recorded, are not considered. For example, geese are in decline in Doñana, but are increasing in northern Europe, where they nest.   

In addition, in my opinion, there are management measures that could be added to the list in the report. The drastic decline in the number of colonial birds such as terns, avocets and black-billed terns may be due in part to the lack of suitable islands for their colonies and it would be possible to create more in fishponds or other areas. Also not considered are the forecasts for the rise in sea level due to climate change and the need to consider measures to avoid saline intrusion in the fresh marsh areas where many species nest.

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