Prolonged incubation behavior by a marbled godwit

On 9 May 1972 I flushed a Marbled Godwit (Limosa fedoa) from a nest containing four eggs in a large field of mulched wheat stubble in northwestern Stutsman County, North Dakota. I revisited the nest on 31 May and on 7, 9, 12, 15, 16, 20, and 21 June, and found an incubating adult on the nest during all visits except 21 June. Another adult was seen near the nest site only on 9 May. On 12 June the eggs looked rotten, and the incubating bird seemed to have a crippled leg. On 21 June Ring-billed Gulls (Larus delawarensis) destroyed the eggs.