The Osprey pair at the iconic LLNF nest pole, extremely visible from the parking area and the Foundation House is already incubating eggs. The couple has been courting and mating over the past 10 days, last seen copulating on April 11. Ospreys usually lay three eggs but rarely lay two or four. The other nest pole visible from the LLNF on the east side of the North Head of Long Pond also has a pair busy with nesting chores.
Both female and male Osprey incubate the eggs with the female taking the greater part and being fed by the male. The eggs hatch from 32 to 33 days later. Because incubation begins when the first egg is laid, the first chick to hatch has the advantage over its smaller and weaker siblings. The smallest chick may die if food is scarce.
The young become active around two weeks old and for around 40 days the female remains at the nest brooding, feeding, and tending the young. The male brings food and his fishing skills have everything to do with whether or not young will survive. The young feather towards the end of this period; pick up food at around 42 days, and take their first flight from 51 to 59 days old. The young continue to depend on the parents for food for at least 10 to 20 days after which point the adults depart, heading south and leaving the fledglings to figure it out. Young raptors are vulnerable, especially just after fledging as they must learn to fly, avoid predators, and catch their own food - none easy tasks. They must fish well enough to fatten up and depart for South America a scant few weeks after leaving the nest. It is a remarkable life cycle.
Should the young make it to South America, they remain there for almost a year and a half, learning to fish and survive, before making their first return trip to North American breeding grounds - usually not far from where they were hatched.
Ospreys returned to the LLNF pole at the North Head of Long Pond on March 21. In 2011 the first Osprey returned to this nest pole four days earlier. Despite the mild winter and early arrival of Ospreys to several mainland and Cape Cod sites, the species returned a little bit later than usual to Nantucket. The male bird was first back and it was not until March 25 that the female showed up. The birds are currently actively next building and engaging in courtship flights.
We are excited here at the LLNF as anticipation for these harbingers of spring make their way back to ACK for another breeding season. The birds should arrive on or around Saint Patrick's Day, March 17, give or take a few days depending on frontal systems and prevailing wind direction.
The LLNF monitors two active Osprey nest poles located on the north end of the North Head of Long Pond between Eel Point and the Madaket Road. Nest #1 is located at the north end of the North Head while Nest # 2 is located half way down the east side of the North Head.
Nest #1, the nest on the very northern end of the pond and easily observed from the south facing deck of the LLNF Foundation House, has historically been the most successful nest at fledging Ospreys on Nantucket since records have been kept. In 2008 this nest fledged 3 young, in 2009, the last breeding season; they managed to fledge 2 young after hatching 3 in a very rainy and difficult breeding season with a couple of Nor'easters in mid-June when the young were a little more than half grown and needed prodigious quantities of fish.
Nest# 2 has laid 3 eggs for the past 2 breeding seasons in 2008 and 2009 but not managed to have any young survive for more than a couple of weeks. Reasons for the nest failure are uncertain; the most likely reason is that the male bird is not a sufficiently skilled fisherman to provide a steady and timely supply of fish, especially in bad weather.
For more information on Osprey Migration than you can imagine check out the following website from the premiere Osprey researcher in the world-Rob Bierregaard who is currently at the University of North Carolina.
PO Box 149
Nantucket, MA 02554
110 Eel Point Road
Nantucket, MA 02554