The Caspian Tern occurs locally throught its range and has probably never been common or widespread during recorded history. The first known nesting of Caspian Terns in New York occurred in 1986 and the species is therefore recently new to the state. There are only two known colonies statewide. This species is highly susecptible to human disturbance of nesting areas. Although trends indicate that numbers have increased in both New York populations since they were established, scarcity of suitable nesting locations away from predation and human disturbance may be a limiting factor in the state.

The Caspian Tern was first confirmed as a breeder in New York in 1986 on Little Galloo Island. The population there has grown from an initial 112 nests reported in 1986 to 1300 nests by 1998 (New York Natural Heritage Program 2008). The maximum number of nests was 1788 in 2005 and has declined to 1376 in 2008 after an outbreak of type E botulism in 2006. A smaller colony of 5 nests was first reported in the second Breeding Bird Atlas in New York on Four Brothers Islands in 2004. The colony has since fluctuated between 34 and 56 nests from 2005 to 2008 (New York Natural Heritage Program 2008).

Populations in Europe and Africa have experienced declines over the second half of the 20th century resulting in the species absence or rarity in some parts of its range. However in North America, trends in some parts of their range appear to be increasing. Despite declines in the Great Lakes populations from 1925 to 1960 (Ludwig 1965), numbers since 1960 have tripled (Wires and Cuthbert 2000). Potentially, this is the result of an increase of forage fishes due to the over fishing of large predator fish in the Great Lakes (Wires and Cuthbert 2000). In recent years, North American populations have also expanded their distribution, moving into new areas. The long-term trends of this species are increasing in New York with the first nesting colony ever documented in 1986. Eaton (1910) and Bull (1974) previously only reported the species as a transient or migrant. The first Breeding Bird Atlas reported the species as a probable breeder in the state (Andrle and Carroll 1988), however, the nesting area was not documented until 1986, a year after the atlas field work was complete.