By Anders Lorenzen

Scientists have warned that in some parts of the UK, spring is starting three weeks earlier than usual. And the evidence is pretty clear; climate change is to blame.

According to the scientists working on one of the longest animal-tracking studies in the world in what they say is the world’s most studied woodland, Wytham Woods in Oxfordshire, UK egg-laying has shifted by three weeks in some parts of the woodland.

Dr Ella Cole from Oxford University is working on the 75- year-long study (started in 1947). Dr Cole explains that their data reveals the cascade effect of nesting, and how that has impacted the surrounding ecosystem and food chain, leading to the conclusion that Spring begins earlier than in previous years.

How birds respond to climate change

The detailed and wide-ranging study is still ongoing. It has produced in total 350 scientific papers so far. And 700-800 nest boxes are checked every year. They have been finding, for example, that around 10,000 caterpillars are needed to feed an average clutch of Great-Tit nestlings in the two weeks between hatching and fledging.

Dr Cole explains that the project has given details about how changing events in the natural world link to the climate crisis. She says it has allowed us to input all aspects of how a population of wild birds operate in the context of climate change. 

Prof Ben Sheldon from Oxford University, who currently leads the Great-Tit project said: “We’re also able to ask how extreme climatic events – increasingly seen as a risk of climate change – affect the population because the length of the study gives us more chance to observe these.”

The 1947 project shows no signs of slowing down, and the checking of 800 occupied nest boxes each year keeps researchers busy. And each season the timing of Spring, the busiest season, becomes ever more unpredictable – and as the climate continues to warm, that unpredictability has come here to stay.

You can learn more about the study here.