by Annette J Beveridge
Spring is upon us. The sound of birds singing and the warmth of the sun is so welcome after the dark nights and the chilly winter months.
It may feel wonderful to us, but we do know that throughout springtime, birds start to build their nests in alignment with available food sources. This is typically around the same time of the year every year.
However, research by US scientists analysed nesting trends and used egg samples available in the Chicago area. It revealed that egg laying is now occurring almost a month earlier than at any time over the last century.
The research published in the Journal of Animal Ecology is understandably concerning. The alterations in temperature may be barely noticeable to us but even a few degrees increase will impact nature. Insects will emerge earlier and plants come into flower at a different time. This is caused through our continued use of fossil fuels.
Birds must adapt their egg-laying to compensate for the shift in pattern. This adds extra pressure as there is greater competition for available food sources.
Researchers considered rising temperatures but were unable to prove this due to insufficient long term data. Instead, researchers decided to monitor the amount of carbon dioxide in the atmosphere instead. By doing so, they were able to source approximate temperatures alongside carbon-dioxide levels which included chemical composition of glacier ice-cores.
The amount of carbon dioxide in the atmosphere over time neatly maps onto larger temperature trends. Researchers found that this correlated with the egg-laying date changes. From this, we can say that spring temperatures and subsequent nesting patterns are being affected by the climate crisis.
Field Museum. “Birds are laying their eggs a month earlier, and climate change is to blame: Hundred-year-old museum collections help show that birds are nesting earlier in the spring.” ScienceDaily. www.sciencedaily.com/releases/2022/03/220325093824.htm (accessed March 26, 2022).
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