Ecologist Julia Ryeland was on the hunt for emu nests. These trampled patches of vegetation, padded with grass and twigs, measure a few feet across but can still be tricky to spot. At Ryeland’s field site a few years ago, about 300 miles northwest of Sydney, Australia, the nests were camouflaged among clumps of low-growing plants. When she found one, she would gather the gorgeous, deep turquoise eggs carefully—each one weighs more than a pound—and take them to a nearby research station. After labeling each egg, Ryeland, a Ph.D. student…
