Offshore wind energy is considered an essential part of humanity’s transition away from fossil fuels, but it is important to understand the consequences that wind farms can have for wildlife. In this study, GPS data revealed how breeding Sandwich Terns avoid offshore wind farms in the North Sea. The study, led by Waardenburg Ecology in the Netherlands, used data from GPS tracking of breeding Sandwich Terns carried out at Scolt Head, Norfolk, and De Putten in the Netherlands between 2016 and 2021. Scolt Head had four operational offshore wind farms nearby (within the distance that Sandwich Terns are known to fly when searching for food), and De Putten had three. The authors examined the terns’ so-called ‘macro-avoidance rate’, which is the rate at which birds avoid entering an offshore wind farm altogether. This avoidance amounts to habitat loss, since the birds will no longer use this area of the sea, and perhaps incur additional energetic costs by flying around wind farms or having to forage in less optimal alternative areas. The results showed that Sandwich Terns reduced their use of the Dutch offshore wind farms areas by 41%, and British offshore wind farms by 54%. Birds were more likely to avoid wind farms the closer together the turbines were. This study’s findings could inform not only the positioning of future offshore wind farm developments, but also their design, as taller, more widely spaced turbines could be preferable to shorter, most densely packed ones in terms of minimising any detrimental effects on Sandwich Terns and related species.

Long distance migrants, such as those breeding in western Europe and wintering south of the Sahara in Africa, face perilous journeys during autumn and spring. During the annual cycle, the habitats they use vary considerably between breeding and wintering sites, as well as on essential migration stopovers in very different landscapes on different continents. There are several geographical barriers to negotiate and large expanses of inhospitable habitat, such as sea and desert, to cross. In this collaborative study, high resolution GPS tracking data were used to investigate how the Nightjar achieves this journey, and the strategy the birds use to locate essential foraging habitat along the way. Small to medium sized migratory birds cannot store enough fat reserves to complete the journey in a single movement. Instead, they must stop to refuel at various stages to successfully complete each subsequent leg of the journey using a series of intermediate locations as ‘stepping stones’. This can be problematic for these migrants, as they first need to find suitable foraging habitat and feed sufficiently to get over the next barrier. Aerial insectivores have the added advantage that they can visually select good looking habits and feed opportunistically en route, but Nightjars can only do this when active during the hours of darkness. The results of this study showed, unsurprisingly, that Nightjars rapidly cross barriers and inhospitable habitats, including Mediterranean Sea, Sahara Desert and equatorial forests. Either side of these barriers, Nightjars generally slowed their migration and spent more time in mixed habits, where they could then more intensively search out locations providing foraging hotspots. In both spring and autumn, around nine separate stops were made en route, each ranging between one and 27 days in duration. This study demonstrates how Nightjars optimise their migratory flights and search for prime stopover sites by selecting areas with very diverse habitat composition, which by their nature support prey hotspots. The birds can then home in upon these with limited effort. It is still not known how Nightjars assess the habitat, but it is likely that they can visually assess the structure in the limited nighttime light, or during better illuminated twilight periods.

Many long-distance migratory bird species are experiencing severe population declines. These declines are being caused by human-driven changes, such as habitat loss and climate change, but the relative severity of these varies in space and time. Understanding this variation is key to understanding where species might be most exposed to population-limiting effects. This study used 10 years’ worth of satellite data from birds tagged as part of the BTO Cuckoo Tracking Project alongside data on human impacts on the environment (including the location of infrastructure, habitat change and climate change) collected via remote sensing to address these information gaps.

The Turtle Dove is a summer migrant to the UK. Its numbers have fallen sharply in recent decades, and it is now one of only six globally threatened species that regularly breed in the UK.

High pathogencity avian influenza hitting seabird colonies and severe marine heatwaves disrupting marine food webs highlight just two of the many threats that seabirds must contend with. This BTO study examines the information needed to come up wtih effective conservation measures for seabird species.