Cormorant Damage To Island Reduced After Approximately 100 Birds Were Killed, 60 Nests Destroyed
MORRISTOWN - Tree damage on a Morristown island caused by nesting cormorants was reduced after a summer's worth of control measures were instituted to cut down on the bird's nesting population there.
This year, American Island, Morristown, saw measures implemented to try to cut down on cormorant numbers there due to the death of many trees that the birds were nesting in. When cormorants nest, the feces they deposit on the trees can eventually kill them.
Approximately 100 cormorants were killed and almost 60 nests were destroyed, according to James F. Farquhar, DEC Region 6 wildlife biologist out of Watertown.
"I do not know the final number taken by the landowner, but probably in the area of 100. We took 37 from the site and removed 59 nests under our authority to protect public resources. This obviously benefited the landowner's desire to protect property as well. While efforts on American Island did not eliminate tree damage, the level was much reduced this year," said Mr. Farquhar.
This summer also saw a drop in the number of cormorant nests destroyed on St. Lawrence River and eastern basin of Lake Ontario islands, mainly because of a decrease in overall numbers, according to the wildlife biologist.
Last year, over 1,300 cormorants nests were destroyed on private islands located on the American sections of the river and the lake, mainly Gull Island. DEC fisheries technicians, hired seasonably, worked with U.S. Department of Agriculture wildlife services staff during the effort to control the fish-eating cormorant population.
He reported that the control program's accounted for the removal of 609 cormorant nests from Gull Island and another 606 taken from private islands on the river. Another 56 were destroyed using shotguns to "break eggs in nests we could not reach," stated Mr. Farquhar.
He said field technicians reported less nests on the river and an overall increase of cormorant numbers on Lake Ontario.
"St. Lawrence River numbers appeared similar; overall nest count was actually down a little. On the lake, local numbers were down slightly. Overall lake numbers were up a bit, mostly due to increases on the western end," said Mr. Farquhar.
While the aim was to remove nests, cormorants were killed during the control program.
"We took 145 in Lake Ontario, fewer than in the past, due to lower overall numbers on our sites," stated the biologist. "We took 40 birds on St. Lawrence River islands, not counting American Island."
The wildlife biologist said that some level of program will likely continue for the foreseeable future.
"On the lake, our efforts are shifting from intensive control towards less intensive maintenance. On the St. Lawrence River, we are really in a maintenance mode, preventing colonization and perpetuation of nesting colonies," said Mr. Farquhar. "Someone once said that cormorant management is like mowing the grass, you have to do it periodically, as needed to meet goals of habitat protection, reduction of fish predation, etc."
Cormorants can reportedly eat their weight in fish a day and anglers are concerned with their impact on the St. Lawrence River and Lake Ontario fisheries, especially the yellow perch fishery, which is a staple of the birds' diet. A 2003 report by DEC showed that cormorants on just three islands on the St. Lawrence River consumed an estimated 23.52 million fish over a three-year period.
