Tern Signals

The black tern (Childonias niger) is a slender, graceful flier with long pointed wings. It is often associated with coastal environments, but the black tern is found inland and presently the only nesting tern species in Pennsylvania. During the breeding season, this bird is relatively easy to identify because of its all-black head, breast and belly and slate-gray coloration above. In the fall, juveniles and molting adults have black and white mottled plumages. Flashing light underwing linings make the black tern especially conspicuous in flight.

The black tern populations have experienced some decline. Although small numbers can be seen during migration even along the major rivers of Pittsburgh, there are barely a handful of nesting sites known in Pennsylvania. This bird is listed as an endangered species in Pennsylvania. They breed annually only in western Crawford County and have also nested in recent years at Presque Isle State Park in Erie County. In the 1990's, Western Pennsylvania Conservancy purchased a marsh at the southern tip of Conneaut Lake to protect one of the few PA nesting sites. When the terns are using this site they can be seen flying above the marsh from a pull-off on the south side of Route 322 at the eastern edge of the town Conneaut Lake. This marsh is now part of State Game Lands #213.

Black terns have been a species of concern in North America because of continent-wide population declines, particularly since the 1960s. Currently, the species is listed as threatened or endangered in six states and is considered of conservation concern in 18 other states and provinces. Breeding bird surveys show that black terns declined significantly in North America at an average rate of about three percent annually (61 percent overall) from 1966 to 1996. This decline largely reflects trends prior to 1980, and trends in the Prairie Potholes of the upper midwest were somewhat reversed in the 1990s. The North American population recently has leveled off or increased slightly. The species still occupies most of its former range, and the continent-wide breeding population probably still numbers in the low to mid hundreds of thousands. Currently the black tern is considered a Migratory Bird of Management Concern in the Northeast.

Reference: Pa. Game Commission and WPC Natural Heritage Program files.

Photo: "Copyright William Hull - http://www.mangoverde.com/")

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