Present-day birds share many similarities with the dinosaurs of the past, and researchers in Canada may have just discovered one of the strongest connections yet. According to a report from CS Monitor, scientists have released a new study that suggests that many dinosaur species likely laid their eggs in a nest, not unlike those of modern birds and reptiles.

The study examined 29 different types of dinosaur eggs. The researchers’ findings suggest that the majority of dinosaur species buried their eggs under dirt and vegetation in their nest, a tactic employed by present-day crocodiles.

A number of other dinosaur species, however, including theropods, or carnivorous, small bipedal species, laid their eggs in open nests much like present-day birds. According to co-author Darla Zelenitsky, an assistant professor of paleontology at the University of Calgary in Canada, “The evolution of open nests and brooding behavior could have allowed small theropod dinosaurs, and obviously birds, to move to other nesting locations other than the ground.”

Using data extracted from ancient fossilized eggshell samples, the scientists have been trying to determine the nesting behavior of various dinosaur species for years. Despite their best efforts, dinosaur egg fossils are extremely difficult to come by.

According to the study’s lead author, Kohei Tanaka, a doctoral student at the University of Calgary’s faculty of science, the lack of available fossils has been a huge roadblock in this field of research. Researchers have used what little information is available to determine how some species built nests and cared after their eggs prior to hatching.

By comparing fossilized eggshells to modern day eggs from birds and reptiles, however, researchers can begin to piece together how different species likely behaved. While some dinosaurs probably kept their eggs warm by covering them with dirt and debris, others regulated the temperature by sitting on their eggs like birds.

A press release from the University of Calgary describing the details of the study can be found here.