State acts to protect nesting colonies of Egrets & Herons

[GLF]

HARRISBURG - Pennsylvania Game Commission officials late last month announced that they, along with officials from the U.S.D.A's Wildlife Services, would soon begin a program to sustain and protect a historic nesting colony of great egrets and black-crowned night-herons - two state endangered species - on Wade Island, in the Susquehanna River. However, this long-considered, last-resort option comes at the expense of the double-crested cormorants encroaching on this relatively unique nesting site.

"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, which has been recognized as an Important Bird Area by Audubon Pennsylvania. Perhaps it is good food resources in the Susquehanna River or it's proximity to the Chesapeake Bay. Whatever the reason, no other place in the state comes close when comparing the number of nesting sites of these magnificent birds.

"Unfortunately, cormorants - also colony nesters - have invaded 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 since the early 1980s and they have never been considered a candidate for the state's species of concern list."

Brauning noted that, during the mid 1990s, up to 1,000 cormorants were regularly seen at Presque Isle State Park in Erie. Since then, their population has continued to expand and they are now common throughout the Commonwealth. 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.

Currently, more than 100 night-heron and 150 great egret nests are on Wade Island. Cormorants were first confirmed nesting on Wade Island in July of 1996. At that time, only a single nest was found. Since then, though, the number of cormorant nests on Wade Island has increased dramatically. In 2005, 59 cormorant nests were confirmed.

"Unfortunately, there is a limited number of nesting sites on Wade Island," Brauning said. "This is a particular problem for great egrets, which prefer nest locations similar to those used by the cormorants. Therefore, we are taking steps to initiate a culling operation by the U.S. Department of Agriculture's Wildlife Services to remove up to 50 cormorants using specialized air rifles and/or suppressed .22 caliber rifles."

USDA Wildlife Services has obtained all of the necessary permits from the U.S. Fish and Wildlife Service to conduct this operation under the direction of the Game Commission. The state Department of Conservation and Natural Resources owns Wade Island and has provided approval for this operation. All culled cormorants will be turned over to the Game Commission for disposal.

"During this operation, extreme care will be taken to not disturb the endangered species nesting on the island," said Harris Glass, USDA Wildlife Services Pennsylvania State Director and wildlife biologist. "The exercise will be stopped immediately if it is perceived that activities are threatening the nesting of egrets or herons."

To ensure public safety, the Game Commission will provide law enforcement assistance or arrange for assistance from the Pennsylvania Fish and Boat Commission throughout the operation. The equipment that will be used is designed to reduce any risks and it will be used in the safest manner possible.

Brauning noted that studies have shown that when nesting cormorants encroach upon colonies of other nesting birds, including both black-crowned night-herons and great egrets, they reduce the amount of nesting space for those other nesting species. In addition, cormorants have been known to take over egret nests and also kill trees as a result of their nesting activity. Several other cases found that cormorant droppings on the leaves and branches of nesting trees apparently caused egrets to abandon colonies.

"In addition to the competition for nesting sites, cormorants also may compete with the herons and egrets for food in the local area around Wade Island," Brauning said. "All three birds feed on fish and while cormorants usually dive deeper than herons and egrets for their food, scientists believe that the feeding areas of the three species likely overlap in the shallow depths of the Susquehanna River."

Brauning stressed that culling a portion of the cormorants was not the first option explored. He noted that in 2004 and 2005, the agency attempted to encourage nesting by egrets and night-herons on neighboring islands. However, that effort was met with limited to no success. For more information on this initial effort, please see "News Release #20-04" in the "Newsroom" of the agency's website (www.pgc.state.pa.us ).

"Trying to lure some of Wade Island's herons and egrets to a nearby island was unsuccessful," Brauning said. "Egret 'decoys' were placed on an island that neighbors Wade Island with hopes of attracting some birds away from the growing cormorant population. The use of decoys will continue, but such efforts generally provide only mixed success and may attract cormorants as well. Other methods to control the success of the cormorant nests (oiling of eggs, use of poles and high-pressure sprays) are not possible on Wade Island, because of the nest height.

"Therefore, lethal removal of the cormorants was determined to be the safest, least-disruptive, most cost-efficient and promising control method."

support of this conclusion, USDA Wildlife Services also has considered all available management options and the adverse effects associated with those options. Wildlife Services has determined lethal control to be the most appropriate management option and does not foresee any significant negative impacts to the other wildlife or the public from this option.