The Black Tern is unique among terns in that breeders have a distinctive black head and sooty-colored body. This small tern nests in freshwater habitats and eats insects as well as fish, the principal diet of most terns (Dunn and Agro 1995).
Black Terns nest semi colonially and forage for aerial insects and aquatic invertebrates in freshwater marshes in northeastern California and in rice fields in the Sacramento and in upper San Joaquin Valleys (Dunn and Agro 1995, Shuford et al. 2001, Shuford 2008b). Surveys conducted during the 1998 El Niño year found 2,213 breeding pairs in the Central Valley, of which 90 percent were in rice fields in the Sacramento Valley, and another three percent were in rice fields in the San Joaquin Valley (Shuford et al. 2001, Shuford 2008b).
During the early nineteenth century, natural marshes in the San Joaquin Valley sustained large populations of Black Terns. With the loss of these breeding areas, the rice fields of the Sacramento Valley have become this species’ stronghold in the Central Valley. The state’s only other stronghold is in the natural marshes of northeastern California (Shuford et al. 2001, Shuford 2008b).
The Black Tern is on the California Bird Species of Special Concern Priority 2 list, primarily due to loss and degradation of breeding habitats.
Black Tern: Leslie Morris and Jim Morris