Different scales of change are likely to be encountered at separate breeding and wintering grounds. However, conditions along the migration route, particularly for long distance, Afro-Palearctic migrants, also vary dramatically in the same location between the spring and autumn. Such varied seasonal habitat changes require considerable flexibility in the capacity for adaptation throughout the annual cycle, which has potential detrimental implications for many migrant species. 

Using GPS tracking data from 29 Nightjars tagged in Britian and Belgium, the birds’ current habitat use during the breeding season, winter, and during spring and autumn migration was determined. Climate change and a range of socio-economic predictions, in combination with environmental conditions, were used to estimate how the extent and location of suitable habitat is likely to change in the future (2081–2100). The main findings indicate that although more suitable habitat may be available in the future in the breeding, wintering and spring migration locations, a substantial reduction in suitable habitat is predicted for the autumn migration. In addition, the length of migration barriers, such as the Sahara Desert is predicted to increase. Therefore, longer migration distances will require greater energy expenditure, which will increase the risks associated with migration and consequently impact survival. 

This study highlights the complexity of future habitat change and how this may vary seasonally and within different parts of the annual lifecycle. It also provides an example of how Nightjars, and many other long-distance migrants, are likely to be impacted by future environmental change.

Climate change and the alteration of land-use and land-cover (LULC) on a global scale presents a notable threat to biodiversity, with a particular impact on long-distance migratory birds. Nonetheless, our comprehension of how these changes specifically affect these avian migrants remains limited. To address this knowledge gap, species distribution models offer a valuable tool as they allow for projecting habitat suitability and provide insights into a species’ ecological responses to changing environmental conditions. In this study, we utilize modelled climate and LULC data spanning from 2015 to 2100, coupled with GPS tracking data and open-source occurrence data of European Nightjars (Caprimulgus europaeus), to assess how suitable habitat might be affected by changes in climate and LULC under different emission and socio-economic scenarios. Our models show that climate change alone may expand suitable habitat, particularly under high-emission scenarios, while LULC change generally exerts a constraining effect across annual cycle stages. While some scenarios indicate overall stability in the amount of suitable habitat, our spatially explicit results reveal that these entail substantial redistribution of suitable habitat which may disrupt migration patterns and increase energetic costs. Our findings underscore the importance of explicitly considering spatial and temporal aspects in assessments of global change impacts on migratory species and highlight the need for targeted conservation interventions in critical stopover zones to safeguard the species' future amidst global environmental change.