Crump Lake is located in the Warner Valley in south-central Oregon, near Adel (OR). All islands and seasonally inundated wetlands associated with the lake are owned and managed by the Oregon Division of State Lands. A low-lying rocky island that was used by a variety of colonial nesting waterbirds in years of low lake levels was located in the central portion of Crump Lake, north of the peninsula that nearly bisects the lake. In the early part of the 20th Century the island supported large numbers of colonial waterbirds each year, but in the 1950s, when the lake dried out, heavy equipment was used to scour the island for Native American artifacts, which resulted in a lower elevation island that was completely inundated in high water years. In the early 1990s, following another drought year, the Oregon Department of Fish and Wildlife attempted to restore the island so that it would offer perennial nesting habitat for colonial waterbirds, but subsequent wind and wave erosion again reduced island elevation so that it was inundated during high-water periods in spring and early summer, preventing nesting on the island. Caspian terns were observed nesting on the Crump Lake island in 2000, when approximately 150 breeding pairs nested in association with a larger colony of California gulls, but no Caspian terns nested on the island in 2001 and 2002 due to high water levels. In 2003, a temporary wooden nesting platform was constructed on the submerged island and equipped with Caspian tern decoys and audio systems to attract nesting terns; Caspian terns nested successfully on the platform (49 breeding pairs), and subsequently on the island (22 breeding pairs), once the lake level had dropped sufficiently to expose part of the island.
In 2008, the U.S. Army Corps of Engineers began implementing the plan “Caspian Tern Management to Reduce Predation of Juvenile Salmonids in the Columbia River Estuary” to redistribute a portion of the East Sand Island tern colony to alternative colony sites in Oregon and California. Crump Lake is one of five sites in interior Oregon/N.E. California where resource managers intend to create Caspian tern nesting habitat as part of this plan. In March 2008, the U.S. Army Corps of Engineers completed construction of a 1 acre island in Crump Lake at the location of the pre-existing island. The island was designed so as to resist erosion and remain well above lake levels, even at full pool, and the surface was covered with gravel and sand to provide nesting substrate for Caspian terns. Caspian tern decoys and audio systems that broadcast tern calls were installed on the island in order to attract terns to nest at the site. Caspian terns successfully nested on the island in 2008 and 2009, as did large numbers of ring-billed gulls and California gulls. In 2009, ca. 670 breeding pairs of Caspian terns raised ca. 120 young terns to fledging at the site.
