Bird migration patterns changing with climate

Researchers in Finland have revealed that some waterfowl are delaying their winter migrations by as much as a month compared to 30 years ago due to the effects of climate change. The study is based on ‘bird counts’ carried out over the past 32 years by volunteers across the region.

In fact, six species out of 15 counted have been found to be setting off significantly later on their journeys. For many birds, a chain from Siberia to Britain is followed, with movement up or down the chain with the seasons. Some birds are now not visiting the last link on the chain - Britain, at all. This means many fewer birds in Britain during winter; white fronted geese for example, have declined by 75 per cent in the last decade.

Along with air temperature, water temperatures are rising even faster, further slowing the flow of birds south during winter. This lack of birds can lead to a knock on effect on some of the habitats usually associated with them. Wetlands in particular are expected to undergo some changes in the coming years.

The next step for the researchers is to determine which birds are simply basing themselves in cooler countries, and which are actually declining globally as a population. The nature of migration makes this difficult, but it is important to understand where conservation and remediation is necessary.

In another study, published in Evolutionary Applications, scientists used a mathematical model to show that biodiversity can promote survival in an ecological community. This means that the more diverse a community is, the more likely the members of that community are to survive the effects of climate change. The theory goes that if two species that rely on each other are altered by climate change, they can fall ‘out of sync’ with each other, causing extinction. With more diverse biomes, there is a higher chance of an alternative ‘mutualist’ to compensate for the changing relationships.