Birds Are Laying Eggs Earlier Likely Due to Climate Change

It’s an annual harbinger of spring: Birds singing, building nests, and laying eggs. But the timetable has been gradually changing. A new study finds that many bird species are building their nests and laying eggs nearly a month earlier than they did a century ago. Researchers compared bird egg information from museum collections with recent bird behavior observations and found that about one-third of the bird species that nest in Chicago have moved their egg-laying to an average of about 25 day

Why Climate Change Matters? To understand why the birds were laying their eggs earlier, the researchers considered climate change as a potential factor. Because they couldn't find temperature data for the area dating as far back as the eggs, they used the amount of carbon dioxide in the atmosphere, which can be used to approximate temperature. The researchers found that atmospheric CO2 concentrations correlated with the changes in when eggs were laid. Although the temperature changed by only a few degrees, it was enough to mean different insects emerged and different plants bloomed. And the researchers point out that it could have an impact on what food is available for birds.