Franklin's Gulls first arrived in southeast Oregon in 1943, but the first nest was not located until 1948. From 1949 to 1964 gull numbers showed annual fluctuations. An increase began in 1965 and continued through 1980. By 1980 an estimated 2500 Franklin's Gulls were nesting on Malheur National Wildlife Refuge, Harney County, Oregon. The species arrives in April and nesting begins by 1 June. Average nest and egg measurements were similar to those from other areas within the species range.
Littlefield, Carroll D. and Thompson, Steven P.
"History and status of the Franklin's Gull on Malheur National Wildlife Refuge, Oregon,"
Great Basin Naturalist: Vol. 41:
4, Article 9.
Available at: https://scholarsarchive.byu.edu/gbn/vol41/iss4/9