Black Tern Chlidonias niger Scientific name definitions

The Black Tern differs from other North American terns in several respects. It is small, has a black head and underparts in breeding plumage, eats insects as well as fish, and nests in freshwater habitats. This bird is described well by Bent (Bent 1921 Bent, A. C. (1921). Life histories of North American gulls and terns. United States National Museum Bulletin 113. Close : 297) as “a restless waif of the air, flitting about hither and thither with a wayward, desultory flight, light and buoyant as a butterfly. Its darting zigzag flight as it mounts into the air to chase a fluttering moth is suggestive of a flycatcher or a nighthawk; as it skims swiftly over the surface of the water it reminds me of a swallow; and its true relationship to the terns is shown as it hovers along over the billowing tops of a great sea of tall waving grass, dipping down occasionally to snatch an insect from the slender, swaying tops.”

The Black Tern nests semicolonially amidst emergent vegetation in biologically rich fresh-water wetlands. Nests are flimsy, often floating, and are easily destroyed by wind or changing water levels. Reproductive success varies greatly. Adaptations to marsh nesting include frequent renesting, low site tenacity, and eggshell morphology suited to damp conditions.

This highly social species often forages in flocks. It migrates mostly through the inland United States, then shifts primarily to marine habitats in winter. There it favors productive marine waters, especially off the Pacific Coast of Panama, and often concentrates where predatory fish have driven small prey to the surface.

Populations of this tern in North America and Europe have declined markedly, at least since the 1960s. In North America, Breeding Bird Survey (BBS) data show an average annual decline of 3.1% over the period 1966 - 1996, with the steepest declines evident prior to 1980. Declines were largest in the prairie provinces of Canada. Loss of wetlands on breeding grounds and migration routes is likely a major cause of these declines, but food supplies may have been reduced through agricultural control of insects and overfishing in the marine winter range.

Recent studies have focused on identifying broad scale habitat suitability through the use of remote sensing, modeling, and landscape level land cover (Naugle et al. 1999b Naugle, D. E., K. F. Higgins, S. M. Nusser and W. C. Johnson. (1999b). Scale-dependent habitat use in three species of prairie wetland birds. Landscape Ecology 14 (3):267-276. Close , Naugle et al. 1999a Naugle, D. E., K. F. Higgins and S. M. Nusser. (1999a). Effects of woody vegetation on prairie wetland birds. Canadian Field-Naturalist 113 (3):487-492. Close , Naugle et al. 2000b Naugle, D. E., K. F. Higgons, M. E. Estey, R. R. Johnson and S. M. Nusser. (2000b). A landscape approach to conserving wetland bird habitat in the prairie, pothole region of eastern South Dakota. Wetlands 20 (4):588-604. Close , Naugle et al. 2000a Naugle, D. E., K. F. Higgins, M. E. Estey, R. R. Johnson and S. M. Nusser. (2000a). Local and landscape-level factors influencing black tern habitat suitability. Journal of Wildlife Management 64 (1):253-260. Close , Naugle 2004 Naugle, D. E. Balck Tern (Childonias niger surinamensis): a technical conservation assessment. USDA Forest Service, Rocy Mountain Region (2004). Available from http://www.fs.fed.us/r2/projects/scp/assessments/blacktern.pdf. Close ), as well as analyses of nest site selection within wetlands (Hickey 1997 Hickey, J. M. (1997). Breeding biology and population dymanics of the Black Tern in western New York. Thesis, Cornell University, Ithaca, NY. Close , Hickey and Malecki 1997 Hickey, J. M. and R. A. Malecki. (1997). Nest site selection of the Black Tern in western New York. Colonial Waterbirds 20 (3):582-595. Close , Mazzocchi et al. 1997 Mazzocchi, I. M., J. M. Hickey and R. L. Miller. (1997). Productivity and nesting habitat characteristics of the Black Tern in northern New York. Colonial Waterbirds 20 (3):596-603. Close ). Analyses investigating habitat and conspecific variables that influence nest success (Maxson et al. 2007 Maxson, S. J., J. R. Fieberg and M. R. Riggs. (2007). Black Tern nest habitat selection and factors affecting nest success in Northwestern Minnesota. Waterbirds 30 (1):1-9. Close , Heath 2004 Heath, S. R. (2004). Nest success and chick survival of Black Terns in Maine: Effects of predation on breeding productivity. M. S. Thesis, University of Maine, Orono, ME. Close ) have elucidated factors influencing predation. In Maine, factors influencing breeding productivity -- including water level increases, food resources, and predation -- have also been investigated (Gilbert 2001a Gilbert, A. T. (2001a). The foraging and habitat ecology of Black Terns in Maine. M.S. thesis, University of Maine, Orono, ME. Close , Heath 2004 Heath, S. R. (2004). Nest success and chick survival of Black Terns in Maine: Effects of predation on breeding productivity. M. S. Thesis, University of Maine, Orono, ME. Close , Gilbert and Servello 2005a Gilbert, A. T. and F. A. Servello. (2005a). Insectivory versus piscivory in Black Terns: Implications for food provisioning and growth of chicks. Waterbirds 28 (4):436-444. Close , Gilbert and Servello 2005b Gilbert, A. T. and F. A. Servello. (2005b). Water level dynamics in wetlands and nesting success of Black Terns in Maine. Waterbirds 28 (2):181-187. Close , Heath and Servello 2008 Heath, S. R. and F. A. Servello. (2008). Effects of predation and food provisioning on Black Tern chick survival. Wilson Journal of Ornithology 120 (1):167-175. Close ). Research on the effects of nesting platforms and investigator disturbance on breeding success (Shealer and Haverland 2000 Shealer, D. A. and J. A. Haverland. (2000). Effects of investigator disturbance on the reproductive behavior and success of Black Terns. Waterbirds 23 (1):15-23. Close , Shealer et al. 2006 Shealer, D. A., J. M. Buzzell and J. P. Heiar. (2006). Effect of floating nest platforms on the breeding performance of Black Terns. Journal of Field Ornithology 77 (2):184-194. Close ) have provided insight into management and research alternatives.

Given the recent declining trends in populations of this species in North America, identifying critical wetland complexes for conservation and filling gaps in our knowledge of breeding ecology and wintering ecology remain important priorities across the its range.

This account deals almost entirely with the North America subspecies of Black Tern (C. n. surinamensis). For details on this species in Europe (C. n. niger), see Cramp (Cramp 1985c Cramp, S. (1985c). "Chlidonias niger Black Tern." In The birds of the western palearctic, 143-155. Oxford: Oxford Univ. Press. Close ).