The timeline:
The first sighting of ospreys on this nest this spring was on March 21st by Ken Edwards. Over the ensuing days a solo osprey, likely a male, visited the next. On the morning of March 24th, a pair of ospreys was spotted on this nest. They subsequently settled. On April 20th, a single egg was first reported. On April 21st a second egg was confirmed.
Incubation
Incubation begins when the first egg is laid. Subsequent eggs are laid one to three days apart; clutches have 2-4 eggs. The female usually takes on most of the responsibility of incubation, seldom leaving except to feed. The male then takes over incubation until her return. Incubation takes from thirty-four to forty days.
Brooding
The first chick to hatch has an advantage over the siblings which hatch a day or two later. The first chick grows quickly and can dominate the nest. In years when the food supply is low, the dominant first chick can usurp the available food supply to the peril of the smaller siblings. This insures that at least one of the year’s brood might survive. The chicks are brooded by the female for approximately ten days. The young are too large to fit under her by this time. She will continue to protect them by covering the young with her wing.
Incubation and brooding quote from “New York Wild” website:
http://newyorkwild.org/osprey/osprey_info.htm
