Under a swirling sky of screeching parents, Yiwei Lu has just placed a trap over the egg of a nesting Greater tern, while Donald Lyons, with Oregon State University, identifies a second trap spot. The team attempts two trapping spots on each round in the hopes a bird will trigger one of them. While they will tag several adult Greater crested terns, they only get to catch one critically endangered Chinese crested tern. In a way, capturing the Greater crested terns helps them get a feel for the process before trying to catch the more vulnerable bird. Placing two traps increases the chance that they will be able to catch the a bird and disturb the colony fewer times.