Birds Are Laying Eggs Earlier Likely Due to Climate Change

The Field Museum's egg collection is filled with hundreds of eggs with the inner contents blown out. Most were collected about 100 years ago. Each egg is stored along with handwritten notes about what bird it came from and exactly what day it was collected. There's not much to the collection after the 1920s when egg collecting was no longer so popular with scientists or hobbyists. These early egg people were incredible natural historians, in order to do what they did. You really have to know the birds in order to go out and find the nests and do the collecting, says Bates. They were very attuned to when the birds were starting to lay, and that leads to, in my opinion, very accurate dates for when the eggs were laid.