State Wildlife Grant - T2-4-R

Franklin’s gull is a long distance migrant that nests over water in large marshes of the prairie regions of North America. Since the 1900s the largest Franklin’s gull breeding colonies in the United States have been located on marshes in North Dakota, yet determinants of colony location and current colony dynamics (recruitment and size) are not known. Limited evidence suggests that even large Franklin’s gull colonies experience recruitment collapses that precipitate rapid shifts in colony location. Knopf (1994) indicates continental populations have declined, but it is unknown if the decline is due to ecological factors (e.g., predation) affecting reproductive success, adult survival, breeding habitat loss, or staging area habitat loss. Therefore understanding colony site selection criteria, factors affecting abandonment and recruitment dynamics is critical for developing conservation plans in the breeding range. The two primary goals of the project are to determine why Franklin’s gull colonies experience recruitment collapses and abandonment, and what factors Franklin’s gulls use to select new colony sites.