As many as 50,000 petrels nest in burrows on Saddle Rock Island off Crook Point, making them hard to reach and hard to study. They fly at night to avoid their primary predator, the seagull, and often range 200 miles out to sea in search of food for their young. But thanks to some dedicated U of O marine biologists, were learning more about a tiny bird and the amazing amount of energy it puts into raising its offspring.