Understanding the impact of the climate crisis on sea bird populations

Different species of birds are being affected in different ways. This can be due to changing ranges of species (how far an individual bird can cover), or their foraging behaviours, or in their range of diet. Species that rely solely on one species of fish will be affected greater by the change in the size of that population for example.

In the UK, around 20 species have been identified as having the marine habitat as their primary foraging resource. Evidence suggests that 11 of these species are negatively affected by the climate crisis and 14 of them are regarded at being at high or medium risk to the effects of the climate crisis.

Food and Foraging

Changes in food sources are having a big impact during the breeding season. Many birds rely on sand eel populations to feed their young before they fledge and there is a limited distance many birds can travel to forage for their food. Sand eels are important as they bridge the food chain gap between plankton and predatory fish and seabirds. The changes in oceanic temperatures are influencing the spawning times of sand eel eggs, which can delay hatch times meaning that they don’t coincide with sea bird nesting times.

READ MORE: Sand eels and their availability as seabird prey

Other species such as herring and capelin are migrating to cooler waters, therefore making it harder for birds to forage particularly during the critical breeding and nesting seasons. This is leading to lower reproductive rates, and ultimately a decline in population.

To complicate matters further, excess dissolved carbon dioxide is leading to ocean acidification, this is also having a negative affect on ocean food chains. For example, phytoplankton and zooplankton have shells that cannot form or dissolve in an acidic ocean, and when plankton declines this has an affect on everything above them in the food chain, including our sea bird colonies.

Weather

Changing weather patterns are also having an abrupt effect on sea bird populations. With the increased number of storms affecting the British Isles, what we may forget is many of our sea birds are at the brunt of them, and although our populations of sea birds are well adapted to the British weather, there are always limits.

Powerful storms can have a severe and instant impact on many sea bird colonies by washing away nests. The increase in storm surges is also having an effect on coastal erosion and as a consequence can cause habitat losses. For species such as Kittiwakes that nest low on cliffs, the smallest increase of sea levels can cause dramatic effect on these low nests.

The changing seasons, weather, and food availability is having an impact on some species with migratory patterns. Many British sea birds undertake long-distance migrations and the impacts on these populations are more complex and harder to measure. Impacts could affect the migratory journey, the breeding grounds, stopover locations and wintering destinations.

Birds do have an ability to adapt to some of the migratory problems, for example, they might necessitate flyer longer distances or towards alternative destinations. However, it is essential to consider the repercussions on the regions they are journeying to. Resting sites during migration play a pivotal role in the successful completion of species' migratory journeys.

Disease

If it's not enough that the affects of the climate crisis are having a negative impact on bird numbers, avian flu outbreaks are taking an unprecedented affect on many species of birds. Kittiwakes, black headed gulls, herring gulls, terns and guillemots are being washed up on many beaches, showing symptoms of avian flu.

What can you do to help

The Royal Society for the Protection of Birds (RSPB) and British Ornothogical Society both undertake huge amounts of research to investigate the affects of climate change, reporting any nests or sighting can be helpful to this process.

In England, Wales and Scotland you can go to the following page Report dead wild birds - GOV.UK (www.gov.uk). If you know the species you can also go to BirdTrack | BTO - British Trust for Ornithology.

As climbers and hill walkers, we can keep checking the RAD to avoid climbing in the bird nesting seasons, and minimising our own affects on bird populations by keeping dogs under close control and keeping clear of any wild birds nests.