Today's blog by Fiona Burns, Senior Conservation Scientist, highlights the publication of an important paper on the EU and UK population of breeding birds.

Today we released a paper with colleagues in BirdLife International and the Czech Society for Ornithology estimating the change in the total number of breeding birds in the EU and UK between 1980 and 2017.  The stark results suggest that in my lifetime around 600 million birds have been lost (our estimates are -557 (-681, -433) to -623 (-803, -468) million from the two methods used); that’s a decline of 17-19%, or one in every six birds being lost.

Big changes in a small number of species

This dramatic overall decline is made up of hundreds of individual species-level changes, both ups and downs.  Amongst increasing species there are an estimated 340m more individuals now compared to 1980 and amongst declining species there are a staggering 900m fewer individual birds.  The eight species showing the largest declines make-up around two thirds of this total decline and the same is true for increasing species.

Species estimated to have declined by more than 50 million individuals across the EU since 1980, clockwise from top-left: House sparrow (-247m), Yellow wagtail (-97m), Starling (-75m) and Skylark (-68m) (c) Saxifraga - Rudmer Zwerver, Ben Andrews (rspb-images.com), Saxifraga - Luuk Vermeer and Ray Kennedy (rspb-images.com).

Many of the species experiencing the largest declines in population are species associated with agriculture and it is well documented that policy driven changes in the way we use our farmland to produce food are associated with declines in biodiversity.  The timing of this impact appears to be earlier in western European countries and there is evidence of declines in farmland birds following countries accession to the EU, and adoption of the Common Agricultural Policy.

House sparrows and Starlings have both declined in agricultural land where they were once highly abundant but are also experiencing large and ongoing declines in urban areas.  For House sparrow in particular much research effort has been put into understanding these urban declines and reduced food supply, air pollution and avian malaria may be involved - but the evidence remains inconclusive.

The reasons underpinning the largest population increases are less well understood.  It is likely that climate change plays a role in some of them, for example harsh winters are associated with lower survival in Wrens. But other factors such as winter feeding of birds in gardens might play a part too.

Species estimated to have increased by more than 25 million individuals, clockwise from top-left: Blackcap, Chiffchaff, Blackbird and Wren, (c) Saxifraga – Mark Zekhuis, John Bridges (rspb-images.com), Saxifraga – Mark Zekhuis and Saxifraga - Luuk Vermeer.

Strong declines in common species

Looking in more detail, a similar number of species have increased to those that have declined, but we see an overall decline because the more abundant species are more likely to have declined or to have declined more strongly.

For many people conservation is synonymous with saving rare species from extinction, but it is equally important to restore depleted populations of abundant species. This is important both from a fundamental point of view, but also because of the role these ubiquitous species play in a healthy environment. 

The loss of hundreds of millions of individuals seems likely to affect the benefits that people get from nature, whether this is pest control on farmland from insectivorous birds, or the pleasure people get from watching spectacular events, such as starling murmurations, and even more importantly the everyday experience of seeing and hearing wildlife around our homes.  Nature connection is good for people in lots of ways.

Hope and opportunities

These results may seem another depressing biodiversity statistic, but there are signs of hope as well.  The overall decline in total abundance is concentrated towards the first half of our survey period and from other work we know that species focussed conservation and EU Nature Directives (the Birds and Habitats Directives) have really helped many bird species.  We also know that there are a wide range of effective ways to manage agricultural land in nature-friendly ways for nature and food production. 

Peregrine falcon populations have recovered across the EU due to a ban on organochlorines in agriculture and increased protection from persecution (c) Verity Hill (rspb-images.com)

Crucially, this year there are several critical opportunities to put in place stronger legislation and international agreements to halt species extinction and restore species abundance.  Countries around the world are developing a new international plan to recover nature (the CBD’s post-2020 Global Framework), which will be finalised at the UN Biodiversity conference, COP 15, in spring 2022.  

The ground-breaking Westminster Environment Act (2021) sets a legal target to halt wildlife decline in England by 2030.  This world-leading innovation is testament to huge public and parliamentary demand to improve the state of nature and to act urgently. Similarly, the developing EU Restoration Law goes further and is set to contain a legally binding target to recover species’ abundance by 2030.

Bird monitoring programmes in Europe are among the best in the world and the rich datasets used in our study will help us to track progress towards these targets. My hope when we repeat this work in years to come, is that we will be able identify and celebrate more signs of recovery.

I want to end by thanking the thousands of dedicated and knowledgeable volunteers who take part in national bird monitoring schemes across the EU, I cannot state strongly enough the vital conservation role they play.

For the full paper in Ecology and Evolution: Abundance decline in the avifauna of the European Union reveals cross-continental similarities in biodiversity change

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