Global warming makes great tits hatch a month earlier

Global warming is causing great tits to hatch a month earlier than 75 years ago, a long-running study has found.

Scientists working on one of the world’s longest animal population studies have discovered that the first springtime great tit egg was laid exactly four weeks earlier than the first in the research in 1947.

Experts said the discovery reveals how Spring advanced an entire calendar month during the study, conducted at the University of Oxford’s ‘living lab’.

the Wytham Woods Great Tit Research is the longest continuous study of an individually marked animal population in the world.

Global warming is causing great tits to hatch a month earlier than 75 years ago, a long-running study has found.
Steve Chatterley/Zenger

For more than seven decades, scientists have monitored the timing and population size of birds commonly found in many gardens across Britain.

It plays a key role in helping scientists understand how populations change in response to the environment – ​​in particular how they cope with climate change and rising global temperatures.

Sir David Attenborough, who has visited the ‘living woods’ of the Oxfordshire countryside several times during his long career, hailed the study’s ability to help increase understanding of the natural world.

He said: “I am delighted to learn of the 75th anniversary of the long-term Great Tit Study at Wytham Woods.

“Having visited several times, I know how fundamental this study, and others like it, have been to our understanding of the impacts of climate change on the natural world.

“Long-term studies like this require a long-term commitment, and I wish the study – and its practitioners – a long and productive future.”

Like many aspects of their biology, the timing of great tit egg laying is influenced by both large and small scale factors, such as climate, social interactions, and the health and behavior of nearby trees. , the scientists said.

Researchers are beginning to understand these factors in terms of potential vulnerabilities and resilience to climate change, experts said.

Professor Lord John Krebs, Emeritus Professor of Zoology at Oxford, and a member of the House of Lords Science and Technology Committee, said: “In the late 1960s when I started my Doctor of Philosophy [the Oxford equivalent of a PhD] on the great tits at Wytham there was a remarkable ‘long term’ record of the population, which I analyzed to understand what factors determined the number of birds in the population.

“At that time, ‘long term’ meant approximately 20 years. Today, thanks to the foresight of those who began the study and many generations of workers in the field, there is a truly unique record that will continue to provide new and important information about the ecology and behavior of bird populations in the wild.”

great tit
For more than seven decades, scientists have monitored the timing and population size of birds commonly found in many gardens across Britain.
Steve Chatterley/Zenger

Chickadees are excellent study species for ecological research because they readily visit nest boxes, breed at high densities, do not travel far from their birthplace, and tolerate scientific monitoring well.

Scientists can individually tag large numbers of nestlings with unique leg rings and track them throughout their lives.

Currently, researchers are using breeding data from 1,209 fixed-location nest boxes at this particular Site of Scientific Interest west of Oxford, along with information on many other aspects of Wytham Woods’ ecology, gathered by other scientists based at the University of Oxford. .

As the study has grown, it has increasingly used new technologies, including electronic tags, remote sensing and genome analysis to understand evolution.

Professor Ben Sheldon, who leads the Wytham Great Tit study, said: “A study of this length relies on the work of hundreds of people, and it has been a great privilege to build on their dedication year after year, to continue the study.

“This continuity has allowed us to use decades of data to understand how changes occur over time.

“One of the most striking changes is that the average great tit is breeding three weeks earlier now than when the study started.

“This change is a clear signal of the effects of climate change on one of our most familiar woodland and garden birds, and it is studies like this that allow us to determine what the consequences of these changes have been and what they might be. be in the future.”

More than 70 doctorates. theses have been produced on this project and more than 350 scientific articles have been published.

Five particularly important findings from studying great tits over the past 75 years include that climate change is having clear effects on familiar biological systems and that birds are adjusting their behavior as well as their breeding decisions so that they produce optimal traits for their specific circumstances.

He also revealed that individual birds can learn complex behaviors from each other, which can lead to the emergence of cultural differences and evolution can occur at surprisingly small scales in space and time. even in birds.

Another finding made in the research was how social networks connect birds across the whole population, but individual birds take very consistent positions in these social networks.

Great Tit bird eggs
Chickadees are excellent study species for ecological research because they readily visit nest boxes, breed at high densities, do not travel far from their birthplace, and tolerate scientific monitoring well.
Steve Chatterley/Zenger

The researchers said they know climate change drives large-scale shifts in the timing of seasonal events, affecting plants and animals around the world.

But the Oxford researchers want to know how much this matters for the survival and reproduction of these organisms and, ultimately, how will they be affected by climate change?

New research, funded by an ERC Advanced Grant awarded to Sheldon, aims to combine measurements of when leaves are produced for hundreds of thousands of trees across Oxford University’s Wytham Woods, with data on the insects and birds that depend on these trees for food.

Oxford researchers aim to determine the extent to which birds are influenced by small- and large-scale effects and how these interact in ecological networks.

Researchers at the University of Oxford’s Department of Zoology hope the next 75 years of study will be as productive and influential as the first seven and a half decades.

This story was provided to Newsweek by Zenger News.

Teresa H. Sadler