Monogamous, ospreys reach sexual maturity at age three and often mate with the same partner for life. Adults return each year to nest in the same area in which they were born. Experienced breeders begin to arrive at old nest sites in late February or early March, while less experienced breeders arrive later in the season and can spend several weeks finding a mate and nesting site. Males arrive before females. Courtship and nest building or repair begin once a pair has reunited. Large, bulky nests are built using branches, corn stalks, shoreline debris and other materials. Nests are often located near the water on tall structures like dead snags, utility poles, channel markers and nesting platforms.
Females lay three eggs between mid-April and late May, which are speckled with beige and brown spots. Incubation lasts for 38 to 42 days. Eggs do not hatch at the same time. The first chick may hatch as many as five days before the last one, and the oldest chick often dominates over the younger nestlings. If food is limited, this behavior can cause younger chicks to starve to death. Nestlings are brooded and fed fish for about 40 days after hatching. After this point, nestlings begin to resemble adults, but have reddish-orange eyes and feathers edged in buff.
About 55 days after hatching, young begin to fly. Families remain together near the nesting site through July, as fledglings learn to fish. Adults begin to migrate to their wintering grounds as soon as fledglings become independent. Juveniles usually migrate during the last week of August.