NEWBURYPORT — Once endangered, ospreys have begun making a comeback in Essex County.
The large birds of prey have been spotted all over the North Shore this past spring and summer, with 26 nesting pairs confirmed last year, according to a report by the Essex County Greenbelt Association.
Locally, nesting pairs of ospreys have been reported in Salisbury, Newburyport and Newbury, and while the Greenbelt report only covers Massachusetts communities, ospreys have also been known to inhabit Seabrook as well.
The latest numbers are an encouraging sign for researchers at Greenbelt, who confirmed 18 nesting pairs in 2012, 14 in 2011 and 10 in 2010. More generally, ospreys have made a major comeback since they were nearly wiped out in the 1960s by unregulated pesticide use, which weakened osprey eggshells and caused widespread nesting failure.
“In the early 1960s, because of DDT and other pollutants, the osprey were almost completely eliminated,” said Bill Gette, sanctuary director at the Joppa Flats Education Center in Newburyport. “With all the work that’s been done since, the water system is cleaner and the osprey aren’t getting all the harmful chemicals, so they’ve really come back strongly.”
According to the Greenbelt report, there are four nesting pairs of ospreys in Salisbury, two in Newbury and one in Newburyport. Gette said the nests can be found easily along the Salisbury side of the Merrimack River near the Route 1 bridge, and within the Parker River National Wildlife Refuge.
“They’re not hard to find during the nesting season,” Gette said. “All throughout the Great Marsh, there are platforms put up by a number of different organizations that have osprey on them.”
Ospreys feed almost exclusively on fish and nest near bodies of water. With wingspans up to 6 feet, they are often seen gliding low over water before diving feet-first and grasping fish in their talons.
“We’ll see the talon plunge first into the water to catch these fish, and off they fly,” Gette said. “It’s a dramatic thing to see.”
To encourage the birds to nest, Greenbelt has constructed more than a half-dozen wooden platforms around the North Shore, which make ideal homes for the ospreys’ large stick nests. The birds are known to seek out almost any tall structure, including the tops of buildings, telephone poles and electric transmission towers.
Further down the coast in Salem and Marblehead, ospreys nested last year on top of navigational day markers, which are used by boaters in open water. There were nests off the Salem power plant and off Forest River Park, and also a nest on the Danvers River on a large transmission tower, according to Dave Rimmer, the Greenbelt director of stewardship and head of its osprey program.
Rimmer credits an estimated 200 volunteer nest monitors and Greenbelt staffers with providing valuable reports last year on osprey activity.
“I’ve seen eight osprey flying at once off Forest River Park,” said Steve Saxe, a volunteer observer from Marblehead, who has photographed and documented nests in Salem and Marblehead.
The Greenbelt stirred up some excitement last year when it set up a webcam on a platform in a salt marsh next to its Essex headquarters, streaming live video. The nesting birds were viewed more than 60,000 times. The live video became a mini-drama, with three eggs producing only one chick, which died.
Two young ospreys were tagged last year with small transmitters to allow officials to follow their migration. The signal was lost from one bird, which presumably died, while the other is still on the move.
“It left from Gloucester and wound its way down the Atlantic coast and is now on the northern coastline of Venezuela,” Rimmer said.
The bird’s progress can be followed at the Greenbelt’s website at ecga.org.
The Greenbelt took on the osprey project not only because they are magnificent birds, but because they serve as a barometer of the environment.
“They are an indicator of the health of a coastal eco-system,” Rimmer said.
The ospreys will start returning in late March.
Nesting osprey pairs in Essex County Marblehead 2 Salem 1 Danvers 1 Gloucester 1 Essex 4 Ipswich 6 Rowley 4 Newbury 2 Newburyport 1 Salisbury 4 2013 Total 26