New York Natural Heritage Program
Common Tern
Sterna hirundo Linnaeus, 1758
Birds

Habitat [-]
Common Terns use a variety of habitats and may be found on coastal beaches or barrier islands, marshes or inland lakes. They nest on sand, gravel, shell, or cobble in open areas with some scattered vegetation or other cover in which chicks can find shelter (Nisbet 2002). Selection of nesting locations may vary by habitat in different parts of the state. On two islands in Oneida Lake, Severinghaus (1982) found Common Terns selected dried grass as the nesting substrate over stony areas when available and these nests hatched significantly more young than nests located on stony substrate. The relatively recent discovery and apparent expansion into saltmarshes since the 1970s (Buckley and Buckley 1980, Burger and Lesser 1978) has lead to some conjecture as to whether beaches are the preferred habitat on Long Island and human disturbance has forced Common Terns to nest in lower quality marsh habitat which is subject to increased flooding (Buckley and Buckley 2000). Selection in the absence of human presence is difficult to determine, however, both habitat types are currently used successfully in New York (Buckley and Buckley 2000). Safina et al. (1989) reported that despite generally lower hatching success and generally greater nest destruction in saltmarshes on Long Island, colonies in both habitats produced similar numbers of fledglings. Most variability in nesting sucess was between colonies and years rather than between habitat types (Safina et al. 1989). Similarly, Buckley and Buckley (2000) concluded that marsh-nesting Common Tern colonies were not at any serious disadvantage when comparing factors such as colony size, establishment, and stability to beach-nesting colonies.

Associated Ecological Communities [-]
  • Brackish interdunal swales
    Temporarily tidally flooded temperate marshes in interdunal swales dominated by salt-tolerant graminoids. Individual swales occur as small patches positioned between fore-, primary and secondary dunes in a maritime dunes system, typically on barrier islands.
  • Great Lakes dunes
    A community dominated by grasses and shrubs that occurs on active and stabilized sand dunes along the shores of the Great Lakes. Unstable dunes are sparsely vegetated, whereas the vegetation of stable dunes is more dense, and can eventually become forested.
  • High salt marsh
    A coastal marsh community that occurs in sheltered areas of the seacoast, in a zone extending from mean high tide up to the limit of spring tides. It is periodically flooded by spring tides and flood tides. High salt marshes typically consist of a mosaic of patches that are mostly dominated by a single graminoid species.
  • Inland salt marsh*
    A wetland that occurs on saline mudflats associated with inland salt springs. The mucky substrate is permanently saturated and seasonally flooded. Plant cover is sparse and the number of different kinds of plants is relatively low.

    * probable association but not confirmed
  • Low salt marsh
    A coastal marsh community that occurs in sheltered areas of the seacoast, in a zone extending from mean high tide down to mean sea level or to about 2 m (6 ft) below mean high tide. It is regularly flooded by semidiurnal tides. The mean tidal range of low salt marshes on Long Island is about 80 cm, and they often form in basins with a depth of 1.6 m or greater.
  • Maritime beach
    A community with extremely sparse vegetation that occurs on unstable sand, gravel, or cobble ocean shores above mean high tide, where the shore is modified by storm waves and wind erosion.
  • Maritime dunes
    A community dominated by grasses and low shrubs that occurs on active and stabilized dunes along the Atlantic coast. The composition and structure of the vegetation is variable depending on stability of the dunes, amounts of sand deposition and erosion, and distance from the ocean.
  • Salt panne
    A shallow depression in a salt marsh where the marsh is poorly drained. Pannes occur in both low and high salt marshes. Pannes in low salt marshes usually lack vegetation, and the substrate is a soft, silty mud. Pannes in a high salt marsh are irregularly flooded by spring tides or flood tides, but the water does not drain into tidal creeks. After a panne has been flooded the standing water evaporates and the salinity of the soil water is raised well above the salinity of sea-water.
  • Sand beach
    A sparsely vegetated community that occurs on unstable sandy shores of large freshwater lakes, where the shore is formed and continually modified by wave action and wind erosion. Characteristic species that are usually present at very low percent cover include various grasses and other herbs.
  • Shallow emergent marsh*
    A marsh meadow community that occurs on soils that are permanently saturated and seasonally flooded. This marsh is better drained than a deep emergent marsh; water depths may range from 6 in to 3.3 ft (15 cm to 1 m) during flood stages, but the water level usually drops by mid to late summer and the soil is exposed during an average year.

    * probable association but not confirmed

Associated Species [-]
  • Roseate Tern (Sterna dougallii)
  • Forster's Tern (Sterna forsteri)