The Common Tern is the most widespread and familiar North American tern, known and appreciated for its attractive plumage and graceful flight, and for its long history as a symbol of the conservation movement. It was widely sought after in the late 19th century for the millinery trade, in which feathers, wings, or entire stuffed terns were mounted on fashionable women’s hats. Slaughter of terns and other seabirds for this purpose peaked in the 1870s and 1880s, and by the end of the century this species was almost extirpated from the Atlantic Coast and many inland areas.
The slaughter of terns, herons, and other birds, was the impetus for the formation of Audubon societies and other conservation initiatives. Their efforts were initially focused on protecting remnant colonies, but culminated in 1918 with the passage of comprehensive bird protection legislation, the Migratory Bird Treaty between the United States and Canada. The Common Tern recovered remarkably quickly, and by the 1930s it had reoccupied most of its original range and recovered much of its original numbers. In the middle of the 20th century, however, numbers began to decline again as burgeoning gull populations took over many of the best breeding sites, and toxic chemicals reduced breeding success in many areas. Since 1970, the Common Tern and other waterbirds that nest on the same islands have become the targets of more diffuse and varied conservation efforts. These have included regulation and control of releases of toxic chemicals, management of dumps and other sources of food for gulls, protection of breeding sites from human disturbance and development, control of predators, and restoration of former sites by removing gulls and enhancing or creating habitat. Breeding populations increased again in most areas along the Atlantic coast during the last quarter of the 20th century, although declines have continued in some inland areas. Numbers in most areas are still well below historical highs, and even maintaining them at present levels requires continuous management at many sites.
The Common Tern readily habituates to the presence and activity of biologists and has been the subject of many intensive studies. In addition to descriptive studies of behavior, foraging, diet, breeding biology, and molt, it has been used for many detailed studies of behavior, ecology, physiology, growth, energetics, contaminants, and toxicology. More than 1.5 million Common Terns have been banded in North America, forming the basis for many studies of migration, dispersal, demography, physiology, age-related biology, and senescence. Extensive studies in Europe and Asia have been summarized in four major handbook articles (Glutz Von Blotzheim and Bauer 1982, Cramp 1985a, Il'Icev and Zubakin 1990, Becker and Ludwigs 2004); another handbook article (Higgins and Davies 1996) summarized information from the Pacific and Australasian regions. Two books have been devoted exclusively to Common Terns: Burger and Gochfeld 1991e on social behavior and Hume 1993 on natural history, as well as a special symposium on the species in western Europe (Becker and Sudmann 1998). Several other books have presented detailed information on Common Terns as well as comparative data on other terns or related seabirds (Bickerton 1912, Marples and Marples 1934, Burger and Gochfeld 1990b, Olsen and Larsson 1995, Cabot and Nisbet 2013). A book chapter by Gochfeld and Burger 1996 summarized knowledge of all the terns of the world.
Since the first version of this account was published in 2002, important new information has been generated on the population genetics of Common Terns (see Systematics), migration patterns and overwintering areas (see Migration), chick growth (see Breeding), adult survival and breeding dispersal (see Demography). Much new information has been generated on the distribution of boreal populations in Canada away from large lakes and on other aspects of the ecology of inland populations (see Habitat, Breeding, and Demography). Declines in numbers breeding in the Great Lakes and the large lakes of Manitoba, combined with genetic evidence for asymmetric gene flow towards coastal populations and with the generally low reproductive success at inland colonies (see Systematics, Breeding, and Demography), have led to increased concern for the conservation status of many inland populations. The history of recent successes and failures in managing and restoring breeding colonies shows that North American Common Terns are heavily dependent on restored and artificial sites, and require continuing management (see Conservation). This revision also updates information on the numbers and trends in many regional and local populations, and on reproductive success at many breeding colonies throughout the southern part of the continental range (see Appendices).
In this revised account, citations to named individuals refer to unpublished data supplied as personal communications; the authors’ unpublished data are cited with initials only (ICTN, JMA, SAO).