What can the eggs tell us?

If you have ever had the opportunity to go behind the scenes at a museum you may have seen many, many cabinets filled with artifacts that aren’t on display. Even just working at our local nature centre, I always found it kind of incredible to look through the different drawers and see what was there. But more than just the awe that one might have at the different items these items have a lot of scientific potential. That was exactly what Bates et al (2022) realized about the egg collection at the Field Museum in Chicago.

The collection includes hundreds of eggs that were collected and tagged with specific details about species, location, and date a century ago. With this information, researchers could track what dates different species laid their eggs. Combine this with modern data and some computer modeling and we see that about a third of the species are nesting earlier, by up to 25 days.

Although, climate change has been linked with changing breeding patterns it is important not to jump to any conclusions. The logical next step would be to see if there is a connection between daily or seasonal temperatures and egg laying, but the temperature records don’t exist for enough of the time period in question. Carbon dioxide levels, on the other hand can be determined through resources like ice cores.

Sure enough, there was a significant relationship between carbon dioxide temperatures, which are known to connect with temperatures. Even a slight change in timing can have a big influence on when insects emerge and plants bloom. So there’s a potential advantage for a bird to lay its eggs earlier. But there are also potential negatives. For example, if one species nests earlier but another one stays the same, there could be new competition that neither species has experienced before.

Both the Arctic and Antarctic have been experiencing record breaking abnormal temperatures. Museum collections have the potential to help us understand the impacts of climate change. But remember, we need to take action on climate change today and across the world.