Five peregrine falcon checks have fledged at nests at two sites in Acadia National Park this year, but for unknown reasons a nest failed at a third site that has yielded chicks in recent years, a biologist at the park said Friday.
Bruce Connery, wildlife biologist at Acadia, said there was a pair of adult falcons at Jordan Cliffs and it is believed they started a nest but then one of the adults disappeared around the middle of June, and the nest failed. Connery said he does not know why the nest at the Jordan Cliffs failed but he said it was not related to the chicks or the nesting.
“My guess would be that one of the adults either left or was killed by a predator like a great horned owl,” Connery said.
On the positive side, the peregrine falcon chicks at the Precipice and Valley Cove have been flying since about July 1, and seemed alert and healthy when they were spotted by researchers, he said. At least one chick at each of the two sites was flying before the others, he said. “They are all flying now and they are doing great,” he said.
Three peregrine falcon chicks fledged at the Precipice and two at Valley Cove, he said.
The park usually waits for the peregrine falcon chicks to fly for five weeks before reopening trails, including the wildly popular Precipice Trail, that are closed in the early spring each year to protect the nesting falcons and chicks. The trails opened July 29 last year and usually open by early August each year.
Connery said the nest failure at the Jordan Cliffs was disappointing because the birds were there and everything seemed to be going along pretty well.
“It would be more understandable if we knew what caused it to fail,” he said, such as the male being attracted to another place.
“We just know we started seeing only one adult …. There was no real rhyme or reason to why it happened.”
Male and female adult peregrines both play vital roles in nesting. Females usually lay eggs in early spring and females incubate the eggs while males hunt and bring food to their mates, according to the web site of the Chesapeake Bay Field Office of the U.S. Fish and Wildlife Service.
Researchers at Acadia don’t know if it was the male or female adult peregrine that disappeared because the feathers of both sexes are mostly similar, but Connery said he would guess that it was the male that left or was killed.
Connery said he was pretty positive it was a “natural event” that caused the nest to fail. He said there is no evidence that human interference was a factor in the nest failure.