A magnificent bird of prey, at home over open water
Vulnerable species in New South Wales (Threatened Species Conservation Act). At a national level it is listed as Migratory on the Environmental Protection and Biodiversity Conservation Act.
What does it look like?
This beautiful bird of prey has distinctively bowed wings, measuring up to 1.7 metres across. As it passes overhead, look out for a barred pattern on the underside of its wings, and white patches under its wings.
The upper parts of its wings and body are dark brown, and the female Osprey has a dark, streaky collar. Both the male and female have a white head, and a blackish stripe running around the eye.
Where does it live?
The Osprey can be found around the world. It breeds in North America, Europe, Asia and Australia, and occurs as a non-breeding migrant in South America and Africa. One particular subspecies, leucocephalus, occurs in Australia, New Guinea, Indonesia, Solomon Islands and New Caledonia.
The Osprey is dependent on water, so this particular sup-species of Osprey is found almost exclusively on the Australian coastline. Occasionally, you may see an Osprey over an inland river – but sightings have been scarce!
While it is common around the northern coast, the Osprey is rare in settled parts of south-eastern Australia. It is only an occasional visitor to southern New South Wales, Victoria and Tasmania.
Ospreys favour coastal areas, especially the mouths of large rivers, estuaries, lagoons and lakes. Here, sheltered from the strong winds and high waves of the open ocean, the Osprey can feed on fish over clear, open water. Ospreys are not usually seen far from shore, but they will venture further offshore from bays and inlets.
In the Pittwater area, Narrabeen Lagoon appears to be the most favoured feeding habitat of the Osprey. Over the last decade, one or two Ospreys have been regularly recorded about Narrabeen Lagoon and the lower reaches of Deep Creek. In the late 1990s, a male and female pair was observed apparently courting. They probably nested in the area, either on the Pittwater or the Warringah side of Deep Creek.
Elsewhere in Pittwater, Ospreys have been recorded in the Pittwater inlet and along the coast at Whale Beach.
What does it eat?
To see an Osprey hunting for its prey is a dramatic sight. These magnificent birds hunt over open bodies of water, soaring over the water searching for fish. When their keen eyes spot their prey, they plummet steeply from the sky, plunging feet first into the water. Their strong talons clutch onto a wriggling fish as they take flight again.
Ospreys feed chiefly on fish – in New South Wales, mullet is a large part of the Osprey’s diet. But they have also been known to eat:
- small terrestrial vertebrates
What is its life cycle?
In other parts of the world, the Osprey may use a variety of sites to build their nests, such as trees, the ground, a cliff – even a power pole or a mangrove tree. In New South Wales, however, the most common nesting site is high up in a dead tree, or in the dead crown of a living tree.
Nests are generally in exposed positions, not more than one kilometer from the water. Built from sticks, the nest is a large, bulky structure. Here, the female Osprey lays and incubates a clutch of 2-3 eggs (and very occasionally four eggs) between July and September. After around 40 days, the chicks hatch. For nine weeks, they stay with the female Osprey, until they are ready to fly. The young birds fledge between October and December.
In south-eastern Australia, individual Ospreys may wander widely. In contrast, breeding adults appear to be sedentary. Pairs of Ospreys become attached to traditional nest sites, returning year after year to raise their young. They will add to their nest over time, until sometimes it becomes a massive pile of sticks and other materials.
It’s believed that Ospreys have nested regularly near Sydney in the past century. After a decline in numbers in New South Wales, the Osprey now appears to be increasing in numbers. In 1990, there were only 45-50 pairs of breeding Ospreys in New South Wales. Since then, numbers have increased. The state breeding population stands at over 80 pairs. However, the only confirmed nesting record south of Port Stephens during this century was a pair that nested but failed at South Kincumber in 1996.
What are the threats?
The Osprey is facing a number of threats to its survival. These include:
- Removal of bushland near the coast (especially the large trees that are used to build nest)
- The degradation of habitat in remnant bushland, especially disturbances to water quality from stormwater runoff or treated effluent
- The degradation of waterways – for example, fish populations in Narrabeen Lagoon could be impacted by pollution, overfishing, increased turbidity (making prey less visible) and other forms of aquatic habitat degradation
- Death by ingesting fish with attached fishing tackle
- Disturbance of birds at nesting sites
What can we do to protect it?
There are many things we can do to protect this beautiful bird. These include:
Updated: 09 Aug 2012