The climate is getting warmer. This will cause all kinds of problems for us – scientists think that eventually people will start moving towards cooler climate regions. However, animals will suffer too. Scientists from the University of Edinburgh conducted a study and found that warmer nights are making birds build nests and lay eggs earlier in springtime. But how?
While we learned to live on our own pace, animals are still living according to their own biological clock. That clock is adjusted to normal seasons, which are characterized by changing weather, which has a strong impact on available food. Climate change is going to completely mess up normal seasons, making everything warmer and extreme weather events – more common. Having that in mind, it is not even that surprising that birds are starting to build their nests and lay eggs earlier in springtime.
Scientists analysed data from 40 Scottish nesting sites over a five-year period. They discovered that night-time temperatures in springtime is a very important factor, helping birds determine the correct timing to build nests and lay eggs. For example, in colder springs birds typically delay offspring matters and wait for a better weather. In the same way warmer nights in spring push nesting season to an earlier time. That is because birds, especially smaller ones like blue tits, are trying to adjust to times when food is the most plentiful. However, they are not adjusting fast enough.
The big problem with warmer springs is that the number of caterpillars also peak earlier. In fact, this process is much faster than birds coming to an earlier nesting time. This is a problem, because chicks may begin hatching after periods when caterpillars – their main food source – are most plentiful.
Scientists also analysed data, gained from two national citizen science projects, and found that warmer nights and birch leafing have very similar effects on the breeding behaviour of woodland birds across the UK. People know that blue tits start nesting when birch trees come into leaf. As temperatures climb, birches are inevitably going to start growing new leafs earlier and earlier. Dr Jack Shutt, one of the authors of the study, said: “Working out what information birds use to time breeding is key to us accurately predicting how this may change under future conditions, and what effect this will have on them”.
When climate change is being discussed, we typically focus on ourselves, forgetting our small wild friends, such as birds. However, that is a huge mistake. These small birds help regulating populations of insects and other pests. If blue tits have problems surviving in this new climate, we will suffer from that as well.
Source: University of Edinburgh