Survival of Semipalmated Plover (Charadrius semipalmatus) nests was compared in areas with and without nesting Arctic Terns (Sterna paradisaea) to determine whether the protection provided to plovers by association with this colonial species is passive or aggressive. Artificial and natural nests placed ≤100 m from terns had similar rates of survival (<10% of all nests lost to predators), and benefited substantially from protection against predators through aggressive behavior of nesting terns. Natural nests had much higher survival than artificial nests when positioned >100 m from nesting terns, suggesting that the presence of incubating adult plovers reduces the probability of nest predation. Nesting in association with Arctic Terns may represent an alternate form of habitat selection by Semipalmated Plovers and suggests that plovers can employ alternate nest defense strategies when opportunities are present.