In early January 2024 a US study put this question back in the news. Researchers led by Hannah Vander Zanden at the University of Florida examined feathers from 871 birds of 24 species found dead at solar and wind facilities in California, and published the results in Conservation Biology. Chemical markers in the feathers showed where each bird had grown up. Many came from far beyond California, and at solar sites most of the dead birds were migrants passing through in spring and autumn. The authors noted that these deaths are far fewer than those caused by cats or collisions with buildings. Even so, they argued that knowing where the birds come from helps target protection.
The California study does not translate directly to Britain. The solar technology is different, and so are the birds and the landscapes. UK researchers and conservation groups have their own body of evidence, and it points to a more nuanced answer.
What the evidence says in 2026
Onshore wind. The most cited UK study, published in 2012 by a team of UK ornithologists and listed by the BTO, followed upland birds at 18 wind farms before, during and after construction. Densities of snipe, curlew and red grouse fell during building work. Grouse numbers recovered once the turbines were running, but snipe and curlew stayed lower. Across the ten species studied, the authors found little evidence of longer-term population declines. The lesson drawn was that construction, and the habitat damage that comes with it, can matter as much as the spinning blades.
Offshore wind and seabirds. At sea, the main concerns are birds colliding with blades and birds avoiding wind farms that sit on their feeding grounds. Species such as kittiwake, guillemot, razorbill, puffin and gannet are routinely assessed for both. The issue is sharper because seabirds were already in trouble. The national Seabirds Count census, published in November 2023, found that 11 of the 21 species with reliable trends had declined since around 2000, and severe outbreaks of avian flu followed after the fieldwork ended. The RSPB backs offshore wind in principle but wants sites chosen on evidence and the combined effect of many projects assessed together. It also favours floating turbines further offshore, which it sees as lower risk for birds feeding near their colonies. When Scottish ministers consented the large Berwick Bank scheme off East Lothian in July 2025, the RSPB strongly objected. The consent requires the developer to show that enough seabird compensation is in place before construction starts.
Compensation in practice. In July 2023 Ørsted placed three artificial nesting towers for kittiwakes off the Suffolk coast as compensation for its Hornsea Three wind farm. In December 2025 Defra launched a Marine Recovery Fund that developers can pay into for larger-scale measures, such as removing rats from seabird islands. In September 2026, Natural England described results from nesting structures as encouraging but early, with only a few nests so far.
Solar farms. A study by the University of Cambridge and the RSPB, published in Bird Study in February 2025, compared solar farms in the East Anglian Fens with nearby arable land. The solar sites held more bird species and more birds per hectare. Sites managed with hedgerows and uncut vegetation held nearly three times as many birds as the surrounding fields, including declining farmland species such as yellowhammer and linnet. The study covered one region, and the benefit depended on how the sites were managed.
The climate side of the ledger. The RSPB calls climate change the greatest long-term threat to birds. A July 2026 RSPB and BTO report found that warming seas and food shortages are already affecting puffins and Arctic terns. Under a high-emissions scenario with no conservation action, some seabird species could decline by more than 70% by 2050.
Why it matters for UK energy
The evidence does not show that renewables as a whole are driving bird declines. It does show that where projects are built, and how they are built and managed, makes a real difference to birds. Good siting and credible compensation are becoming conditions for consent, especially offshore. For more on how sites are chosen, see choosing a location for wind turbines and our overview of solar energy.