The Pennsylvania Game Commission along with the U.S. Ag Department’s Wildlife Services have renewed a program to sustain and protect a a historic nesting colony of great egrets and black crowned night herons, two state endangered species, on Wade Island, a three acre isle in the Susquehanna River near Harrisburg. The effect includes the limited culling of double crested cormorants increasingly dominating the canopy space on the relatively unique nesting site. Culling was first used in 2006, and again in 2011 and 2012.
“Wade Island is home to the state’s largest nesting colony of black-crowned night-herons and great egrets, both of which are on Pennsylvania’s endangered species list,” said Dan Brauning, Game Commission Wildlife Diversity Section supervisor. “It isn’t clear what brings these colony nesting birds to Wade Island. Perhaps it is good food resources in the Susquehanna River or its proximity to the Chesapeake Bay. Whatever the reason, no other egret/night-heron nesting colony in the state comes close to matching Wade Island. It is by far the state’s largest and probably its most vital.
“Unfortunately, double-crested cormorants – also colony nesters – have pushed their way into the night-heron and egret nesting area, and the nesting activity of the cormorants has increasingly become a concern. While cormorants were at one time rare in Pennsylvania, populations have steadily increased. In fact, populations of double-crested cormorants have been increasing rapidly in many parts of the U.S. since the mid-1970s, and their abundance has led to increased conflicts with various biological and socioeconomic resources, including recreational fisheries, other birds, vegetation, and fish hatchery and commercial aquaculture production.”
In the latest survey, conducted on May 2, the number of great egret nests decreased slightly from 185 to 181, and the number of black-crowned night-heron nests dropped from 67 to 48, compared to the survey conducted in May 2012. This is the second-lowest number of night-heron nests in the 28 years of nest surveys on Wade Island.
Brauning noted that extreme care is taken to not disturb the endangered species nesting on the island. Culling efforts will be stopped immediately if it is perceived that activities are threatening the nesting of egrets or herons.
For more information on great egrets or black-crowned night-herons, please visit the Game Commission’s website (www.pgc.state.pa.us), click on “Wildlife,” then choose “Endangered and Threatened Species,” and then choose either “Great Egret” or “Black-crowned Night-heron” in the “Endangered Species” section.