Solar Farms and Birds in Europe: Where the Transition Helps, Where It Hurts
Spain generated more than a fifth of its electricity from solar last year, and it is building fast. That is good news for the climate and a live question for birds, because the Spanish interior is also the stronghold of Europe's steppe birds — species that need exactly the flat, open, sparsely vegetated land that solar developers find easiest to build on. The research of the past two years is less a verdict than a set of instructions.
The problem is siting, not panels
A study published in Ardeola, the journal of the Spanish Ornithological Society, mapped where solar photovoltaic plants were built in Andalusia against how favourable the land is for three threatened steppe species: the Great Bustard, the Little Bustard and Montagu's Harrier. More than half of the surface covered by PV installations up to 2020 overlaps areas rated highly favourable for at least one of them.
That is the core tension. Solar needs sun, low relief and cheap land; bustards need the same low relief and dislike anything tall enough to perch on, because it gives predators an advantage in a landscape that is otherwise a horizon. The study's recommendation is strategic planning rather than prohibition: decide regionally where the energy transition goes, instead of approving plants one at a time.
The mitigation that often doesn't mitigate
Spanish law requires developers to offset harm to wildlife, and in practice the standard gesture is a row of nest boxes beside the panels. An analysis of 130 environmental impact assessments from solar developers, led by Jesús M. Avilés at the Spanish National Research Council, found the boxes are frequently counterproductive.
Boxes designed for cavity nesters such as Little Owls and European Rollers get installed in treeless country where those species would not naturally be; generic boxes are bought without regard for local conditions; and 94% of the assessments did not say what the boxes were made of, even though material affects breeding success — blowfly larvae are less of a problem in aspen boxes than plywood ones, and nest predation is lower in pine. Placement is worse still: in a region where summer temperatures touch 45°C, boxes next to panels catch full sun, and nestlings can simply die of heat. And any box left unoccupied tends to be taken by jackdaws or starlings, colonial nesters that then compete with the species the box was meant to help.
It is not a story about boxes being useless. A study of installations in Extremadura found carefully placed shelters improving European Roller breeding success — the difference was thought, not equipment.
And then the panels turned out to be habitat
Meanwhile, field data keeps showing that a solar plant is not a desert. Researchers at the University of Málaga spent two and a half years studying a 150 MW, 299-hectare plant in Seville province and recorded six raptor species using it — Black Kite most often, then Common Buzzard and Common Kestrel, with 121 observations of birds perching, 120 of flight, 47 hunts and 29 bouts of soaring, and no collisions or related deaths observed. Panel edges, posts and fences are perches, and the grass between rows holds the voles and insects that raptors eat.
Independent consultancy surveys reported by the Spanish photovoltaic association UNEF found the same pattern in species counts: 32 bird species inside a plant at Minglanilla in Cuenca against 19 in the neighbouring farmland, 39 against 34 at Revilla Vallejera, 31 against 25 at Trujillo — including species of conservation interest such as stone-curlew, Little Bustard, Roller, Little Owl and Lesser Kestrel.
Britain shows a similar result. Research by the RSPB and the University of Cambridge in the arable landscape of East Anglia found solar farms held more species and more individual birds per acre than the surrounding farmland, and that the effect depends on management: sites with hedgerows, mixed habitats, flowering plants and relaxed mowing held nearly three times as many birds as adjacent arable land. Corn buntings, greenfinches, yellowhammers and linnets benefited most — birds that are otherwise disappearing from British farmland.
What good looks like
Europe already has a working model for the hard end of this problem. LIFE EUROBUSTARD, a nine-country project coordinated by the Austrian Society for Great Bustard Conservation with a budget of about €22 million, is built around the unglamorous measures: purchasing 91 hectares for habitat, restoring 287 hectares, burying 28.6 km of medium-voltage power lines and marking 110.8 km of high-voltage line to reduce collisions, rescuing at least 1,000 clutches, and tagging 375 bustards to find out where they actually go. Because bustard collisions cluster on power lines rather than solar panels, the wiring matters as much as the siting.
The test is planning, not technology
Put the two halves together and the conclusion is not that solar is bad for birds or that it is good for them. A solar plant sited on steppe bird strongholds and built without thought is a net loss; a plant on already-degraded arable land, managed with hedges, flowering margins and unmown strips, resembles the wildlife-rich farmland that European agriculture largely stopped providing. Europe's energy transition will be a land-use decision taken hundreds of times, region by region. The studies exist. The question is whether they reach the planning committee.
Listening to the birds in the argument
Three of the species at the centre of the Spanish studies, plus the bird that is both a steppe specialist and the reason nest boxes get installed at all.