What to Know About the Osprey in Uganda?

The Osprey in Uganda is one of the African birds in Uganda seen during Uganda birding Tours. Also called river hawk, and fish hawk, the osprey is a diurnal, fish-eating bird of prey with a cosmopolitan range.

It is a large raptor, a sole member in the Pandionidae family, reaching more than 60 cm in length and 180 cm across the wings and a body mass that ranges from 0.9 to 2.1 kg.

The typical lifespan is 7–10 years, though rarely individuals can grow to as old as 20–25 years.

How Does the Osprey in Uganda Look Like?

]The osprey differs in several respects from other diurnal birds of prey. Its toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved.

The osprey and owls are the only raptors whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. This is particularly helpful when they grab slippery fish.

The upperparts are a deep, glossy brown, while the breast is white and sometimes streaked with brown, and the underparts are pure white.

The head is white with a dark mask across the eyes, reaching to the sides of the neck. The irises of the eyes are golden to brown, and the transparent nictitating membrane is pale blue.

The bill is black, with a blue cere, and the feet are white with black talons. A short tail and long, narrow wings with four long, finger-like feathers, and a shorter fifth, give it a very distinctive appearance.

Male and female appear fairly similar, but the adult male can be distinguished from the female by its slimmer body and narrower wings.

The breast band of the male is also weaker than that of the female, or is non-existent, and the underwing coverts of the male are more uniformly pale.

It is straightforward to determine the sex in a breeding pair, but harder with individual birds.

How Does the Osprey in Uganda Sing and Make Calls?

The call is a sequence of sharp whistles, described as cheep, cheep or yewk, yewk. If disturbed by activity near the nest, the call is a frenzied cheereek!

How Does the Osprey in Uganda Feed?

Fish make up 99% of the osprey’s diet. It typically takes fish weighing 150–300g and about 25 to 35 cm in length, but the weight can range from 50 g to 2 kg. Virtually any type of fish in that size range are taken.

Ospreys have vision that is well adapted to detecting underwater objects from the air. Prey is first sighted when the osprey is 10–40m above the water, after which the bird hovers momentarily then plunges feet first into the water.

Occasionally, the osprey may prey on rodents, rabbits, hares, amphibians, other birds, and small reptiles.

How Does the Osprey in Uganda nest?

The Osprey`s nest is a large heap of sticks, driftwood, turf or seaweed built in forks of trees, rocky outcrops, utility poles, artificial platforms or offshore islets.

As wide as 2 meters and weighing about 135 kg, large nests on utility poles may be fire hazards and have caused power outages.

It can nest in a number of 5 to 7 nests in a year. It has a tendency of renovating nests and some of them can be used for over 70 years.

How Does the Osprey in Uganda breed?

The osprey breeds near freshwater lakes and rivers, and sometimes on coastal brackish waters. Ospreys reach sexual maturity and begin breeding around the age of three to four, though in some regions with high osprey densities, they may not start breeding until five to seven years old, and there may be a shortage of suitable tall structures.

If there are no nesting sites available, young ospreys may be forced to delay breeding. To ease this problem, posts are sometimes erected to provide more sites suitable for nest building. Ospreys usually mate for life. Rarely, polyandry has been recorded.

How Does the Osprey in Uganda Reproduce?

The female lays two to four eggs within a month, and relies on the size of the nest to conserve heat. The eggs are whitish with bold splotches of reddish-brown and are about 6.2 cm × 4.5 cm and weigh about 65 g. The eggs are incubated for about 35–43 days to hatching.

The newly hatched chicks weigh only 50–60 g, but fledge in 8–10 weeks. When food is scarce, the first chicks to hatch are most likely to survive.