Black tern numbers plummet in Great Lakes wetlands

The once-abundant black tern (Chlidonias niger) is far less abundant in Great Lakes wetlands, a victim of habitat loss and invasive plant species. And there’s a high risk that more colonies will be abandoned, according to a new study. Since 1991, the number of active black tern colonies has plummeted nearly 90 percent, the study found.

“Decline of black terns in the Great Lakes region has been severe, and preventing abandonment of remaining colonies is an important stop-gap measure for maintaining the bird’s presence until the causes of its decline are better understood,” study authors Katherine Wyman and Francesca Cuthbert of the University of Minnesota wrote.

“Many scientists view continuing wetland habitat loss and degradation as a major barrier to black tern conservation in North America,” they said in a new article published in the journal Wetlands Ecology and Management. And fewer breeding sites increases the birds’ vulnerability to natural disasters.

Terns, which feed on fish and insects, generally nest in deep-water wetlands colonies with two to 50 breeding pairs. Their nests are built on floating layers of plants that are hard for scientists and predators to reach.

Source: Capital News Service, Dec 1, 2017
http://news.jrn.msu.edu/capitalnewsservice/2017/12/01/black-tern-number…