Osprey (Pandion Haliaetus) :: Raptor Facts & Information

Informative site containing, information on Osprey. This specialist raptor, also known as the Fish Eagle, Sea Hawk or Fish Hawk. Osprey are a medium sized raptor, Latin Name: Pandion Haliaetus.

Osprey on Fraser Island Australia

Turning the fish

bird watching

Breeding

The Osprey’s nest is large and permanent, generally near water and at the top of a large tree. The tree may be alive or dead, but preferably should be strong enough to carry the weight of the nest, which consists of an immense mass of dried branches, interwoven with other materials, such as stakes, rope, strips of old cloth, plastic, and even caribou antlers.

To build its nest, the Osprey gathers branches from the ground or breaks them off trees by flying at them. Most construction takes place early in the nesting season but the Osprey may add to its home throughout the summer. In late summer, the bird spends a great deal of time repairing the nest for use in the following year. On average, the nests are 30 to 60 cm deep and 1 m in diameter, but some are more than 2.5 m across. Early in the season, a small hollow accommodates the eggs, but the nest grows flatter as the nesting season advances. Each year, the Osprey adds materials, and as a result, the weight of the nest sometimes causes it to slide down the trunk of the tree.

Generally, the Osprey defends its territory against other large birds such as eagles, owls, gulls, and the Great Blue Heron, which will not hesitate to take over its nest. The Osprey frequently takes the precaution of building more than one nest in its territory, especially if one year it does not manage to have young.

Some couples share the same nest year after year. At the start of the breeding season, when they are pairing or reaffirming their bond, they perform a spectacular display. The male repeatedly flies high into the air, hovers for a few seconds, dives, and reascends in a sweeping arc. Sometimes the female participates in a modified version of this display, making a show of pursuing the male. In another type of ritual display near the nest, the male flies laboriously, body arched and feet dangling below, often holding a fish or a branch in his claws.

According to estimates, nesting females lay an average of three buff-colored eggs with dark brown speckles. The male takes little part in incubation, or warming the eggs until they hatch, and devotes most of his time to fishing. He is the sole provider for the family during the month of incubation and the subsequent month, when the growing chicks demand more than six fish per day. If food is abundant, two out of three chicks are usually able to fly after seven to nine weeks of constant parental care. Predation on eggs and young birds by crows, ravens, owls, gulls, and raccoons does not usually happen unless human activity has disturbed the parents.

According to the most recent estimates, about half of young Ospreys die in the first year; the mortality rate in subsequent years is between 16 and 19 percent. Available banding data (20 000 individuals have been banded in the last 60 years), indicates that Ospreys can live for 15 to 20 years; however, some individuals have lived much longer. The longevity record for the species is held by a banded bird that died, probably from a bullet, at age 35. Unfortunately, we don’t know whether this individual had bred every year up to its death. The greatest recorded number of breeding seasons for a single bird is 23.

Out for morning Hunt

An Osprey with its wings pulled back, can reach incredible speeds, this bird is Stooping before diving feet first in the water to snare its prey.

Ornithology