New York Natural Heritage Program
Least Tern
Sternula antillarum Lesson, 1847
Birds

Threats [-]
Least Terns nest on beaches and are threatened by human disturbance, increased numbers of predators associated with human development, beach driving, and vegetative succession of their limited remaining habitat. Habitat loss due to coastal development has restricted the birds to few remaining open nesting habitats that aren't inundated with people during the nesting season. Burger (1984) reported high rates of nest failure and low reproductive success among colonies in New Jersey. Nests failed due to predation by rats and crows as well as human disturbance. Nearly half of all deserted colonies (25 of 55 or 45%) failed due to human disturbance involving off-road vehicles and people walking through the colonies prior to their desertion. Remaining habitats are projected to become increasingly scarce with rising sea-levels due to global climate change and storm surges that flood nests.

Conservation Strategies and Management Practices [-]
Management for this species involves protecting the nesting areas and limiting disturbance to them. If nest failure rates are high and due to a few individual predators, removal including live-trapping and relocating raccoons and skunks may be necessary and effective (Burger 1989). Electric or snow fencing may be needed in areas where dogs, foxes, or raccoons pose a persistent problem (Burger 1989). Rats should be trapped and exterminated when present. Periodically reducing vegetation to keep it minimal may be needed to keep limited available habitat open in well-established colonies during periods where natural overwash of sand and scouring from flooding is not occuring. Burger (1989) reported that it was easier to remove small amounts of vegetation regularly rather than waiting until it was well-established. Posting and fencing colonies with conspicuous educational signs and limiting ORV traffic near nesting and chick foraging areas are highly beneficial (Burger 1989). Burger (1989) reported the most effective protection for Least Tern colonies was the presence of a full-time warden throughout the day for five or more days a week.

Research Needs [-]
Nest productivity estimates are needed in addition to the population surveys. This will determine if colonies are successful at producing offspring to ensure long-term viability and to determine whether some colonies may be population sinks, where enough juveniles aren't being reproduced to replace the adults. If nest productivity is low causes of nest failure at specific colonies should also be identified so that action can be taken.