Plenty of fish in the sea? Seabird breeding shows impact of commercial fisheries in the North Sea
New research led by the BTO shows that the UK’s internationally important seabird populations are being affected by fishing activities in the North Sea. Levels of seabird breeding failure were higher in years when a greater proportion of the North Sea’s sandeels, important prey for seabirds, was commercially fished. The results demonstrate that seabird breeding can show how these key species are responding to environmental pressures before such changes become evident at the population level. Detecting such impacts as early as possible is a priority, as the management of the marine environment is changing, with expansion of offshore developments, the introduction of marine protected areas, and modification of fishing discards policy.
Moving with the times? Why the timing of bird migration is advancing when individuals are not
The BTO is involved in new research showing that young birds are the trend-setters when it comes to migration. It had generally been believed that the flexibility of individuals to respond to warmer springs lies behind the phenomenon of advancing migration. In this paper, focusing on the changing arrival dates of Black-tailed Godwits in Iceland, the authors show that individual, colour-ringed birds are not changing their schedules over time. Instead, it is the earlier spring migration of birds hatched in more recent years that lies behind the observed pattern of advancing arrival for the species.
Wet winter conditions and warm springs advance migrant breeding seasons
Migratory birds are likely to be particularly vulnerable to climate change because they can be affected by changing conditions on the breeding grounds, wintering grounds or passage areas in between. New research by the BTO has considered the potential for changes in conditions in Africa to ‘carry-over’ and affect Afro-Palearctic migrants during the breeding season. Using a unique dataset collected by volunteers contributing to the Nest Record Scheme over a 46-year period, the study showed that the amount of African rainfall influences the subsequent timing of nesting of 19 species, including Sand Martin, Swallow and Redstart. Birds laid their eggs earlier after wetter African growing seasons, suggesting they were in better condition and therefore able to leave earlier, travel faster or produce clutches more rapidly on arrival. However, the importance of this effect is relatively small when compared to the impact of spring temperature on the breeding grounds. This suggests that increasing temperatures in the UK are largely responsible for the observed trend towards earlier breeding, even in long-distance migrants.
High flying birds at greater risk of collision with offshore wind turbines
New research by the BTO reveals that most seabirds fly near the sea surface, avoiding collision with wind turbines by flying under the blades. Those birds that fly higher above the sea are at greater risk of collision. Building offshore turbines higher above the sea surface, or installing fewer large turbines instead of several smaller turbines, could reduce the number of collisions.
Britain's nature networks future-proofed for birds
Protected area networks, where several sites are legally protected because of their importance for particular species or habitats, are one of the main conservation tools for reducing biodiversity loss. However, it is unclear how effective these networks might be as the species and habitats for which they are designated respond to climate change. New research led by the BTO provides the most compelling evidence yet that while British bird populations are being affected by climate change, and will continue to be, the network of sites established to protect them under European law is resilient to these changes and will remain so.
Using high quality data on the abundance of 62 seabirds and waterbirds collected over 30 years, scientists predicted population declines of at least 25% by 2080 for more than half of the 62 species considered under 4˚C global warming scenario. In some cases, falls were of more than 50%. Species such as the Arctic Tern, Guillemot, Eider and Bar-tailed Godwit were particularly badly affected. However, other species, like Avocet, Snipe and Common Tern, were projected to increase in numbers. Such alterations highlight the need for protected area networks to keeps pace with bird population trends.