Model I birds, the kind that lived during the Age of the Other Dinosaurs, may not have brooded their eggs. Today, birds sit on their eggs in such a way that the adult bird’s down surrounds the ovoids, and warmth from the adult can keep the eggs at a constant temperature. Depending on the bird, you may find additional intersting adaptaitons. For example, Penguins use their own feet as a nest, placing the egg there. One adult broods the egg for a long period (days, in some species) and then swaps with the other adult, with the swapping being very ritualized in some cases. Like this egg swqap between parent Adelie penguins (Tip: this video does not show the actual swap): Continue reading The Early Bird Crushes The Egg →