|Least Terns (Breeding Pairs)|
|4-State Least Terns (Breeding Pairs)|
The least tern (Sternula antillarum) is the smallest of American terns. They are migratory birds that winter in Central America, the Caribbean, and Northern South America. Breeding colonies appear along either marine or estuarine shores of the coastal United States, or on sandbar islands in large rivers throughout the interior of the United States. The least tern hunts primarily in shallow estuaries and lagoons, where small fish are abundant. Once they have spotted their prey they plunge into the water in a spectacular aerial dive to catch it. The least tern’s favored nesting habitat is prized for human recreation, residential development, and alteration by water diversion, which interferes with successful nesting in many areas.
Abundance of least terns indicates whether there is sufficient protected beach habitat for coastal birds and sufficient food supply of forage fish in coastal waters.
Least terns, a threatened species in New York and Connecticut, live in large colonies on the beach and plunge into nearby waters for food. Predators, human disturbances, and tidal flooding can disrupt tern nesting sites, but the terns have the potential to recolonize in other beaches within a four-state region that also includes Rhode Island and Massachusetts. The least tern population has remained relatively stable among the southern New England/New York region since 1990. In 2011, there were 7,078 least tern pairs in the region, 735 pairs above the 20-year average.
In 2011, after several years of general decline, the least tern count in Connecticut was considerably higher than in the two years prior and this higher number of terns is encouraging (although it may show up as a decrease in a neighboring state). In 2011, approximately 361 pairs of least terns nested along the shoreline in Connecticut, an increase of 401 percent increase from 2009 when there were 90 pairs. The largest number of terns were found at Sandy Point in West Haven where more than 400 adults were observed there in May and June. In New York, the total number of least tern breeding pairs throughout the North Shore of Long Island has been declining over the last ten years. This trend is similar to the overall decline across Long Island as a whole.
The New York dataset for this indicator includes monitored sites on the North Shore of Long Island (Long Island Sound) and additional sites in Peconic Bay and Shelter Island in the North Fork of Long Island. LISS assesses this entire sub-region of Long Island for the least tern indicator because the birds frequently re-nest and might move from a Peconic Bay or Shelter Island beach to a Long Island Sound beach and back in the course of a year. LISS also maintains the same dataset for its other beach-nesting indicator, piping plovers.
New York data from 1990 to 2001 is currently not available.
Barrier beach habitat is an important breeding ground for many coastal birds. The photo shows least terns at one of these beaches, Sandy Point in West Haven, Connecticut. The least tern is considered a threatened species in New York and Connecticut. Photo by Julian Hough.