Climate change will have a massive impact on biodiversity in many ways that we do not fully understand yet. Recently, we learned that the changing climate could disrupt insect evolution. In a new study, researchers have found that the changing climate could cause birds to start breeding too early or late in the season, which will mean that they will have fewer young. Birds are finding it harder to know when it is spring and time to breed due to rising temperatures, according to a study published in Proceedings of the National Academy of Sciences. Climate change has meant that springlike weather occurs earlier, meaning that birds are unable to keep up, according to the researchers. Essentially, there is a mismatch between the start of spring and the readiness of the birds to reproduce, and this is only likely to get worse as the world warms. When birds start breeding too early or too late in the season, they produce a lot fewer young. This could have massive consequences that could prove cataclysmic for many bird populations. Typically, the breeding seasons of birds begin when the first green plants and flowers appear after winter, which is happening earlier and earlier as the climate warms. “By the end of the 21st century, spring is likely to arrive about 25 days earlier, with birds breeding only about 6.75 days earlier. Our results suggest that breeding productivity may decrease about 12% for the average songbird species,” said the study’s first author, Casey Youngflesh, in a press statement. Youngflesh is a post-doctoral fellow at Michigan State University. According to Morgan Tingley, senior author of the paper, scientists have been hypothesizing for more than 30 years that animals could become mismatched from plants as spring seasons begin earlier. To investigate this, Youngflesh, Tingley, and the other researchers turned to a large-scale collaborative bird banding program which was run by the Institute for Bird Populations. Using these records, they calculated the timing of breeding and the number of young produced by 41 migratory and resident bird species in North America between 2001 and 2018. They then checked satellite imaging to see when vegetation began growing around the sites where these birds are found. They discovered that each species had an optimal time to breed and that the number of young birds produced decreased when spring arrived very early, or if the birds began breeding early or late relative to when springtime arrived.
