Our Magnificent Ospreys

Osprey in flight, Lake Wylie, South Carolina. Photo: Gareth Rasberry/Wikipedia
Osprey in flight, Lake Wylie, South Carolina. Photo: Gareth Rasberry/Wikipedia

Watching an osprey soar and hover high in the sky is a fascinating sight. It becomes even more appealing if, like me, you are lucky enough to live near a breeding pair of these majestic birds. 

I spend a third of the year in Florida and the rest of the year on my home island of Curaçao in the Caribbean, and it might be our common travel arrangements that makes me feel so attracted to these birds of prey and want to learn more about their habits and customs.

Over the last few years two ospreys allowed me a glimpse into their lifestyle, providing plentiful opportunities to photograph them while in Florida. In Curaçao it was harder to catch them on camera as they use the island only to and rest and refuel during their south/north migration, if in fact they migrate at all. Unlike their northern cousins, satellite tracking proves that not all Florida and California ospreys do so.

One of the most widespread birds of prey, ospreys are found on every continent in the world except Antarctica. The North American osprey migrates to the Caribbean or even further to Central and South America. Their journey may take up to 45 days. They travel by day, using thermals to gain height over land and migrate more slowly than many birds, stopping at favorite feeding sites along the way. Cuba and Hispaniola are key migration hubs for eastern ospreys. In Curaçao we usually observe them between August and March. Satellite tracking is a powerful tool for observing migration behavior. It turns out that each bird travels alone and follows its own route. Females tend to leave earlier.

Feeding time – Almost all of the Osprey’s diet consists of live fish. Photo: Els Kroon

It is a joy hearing their sharp and compelling whistle when returning to our Florida home, strategically situated next to a freshwater pond, almost under the wide branches of an ancient oak tree that has some dead branches reaching to the sky. The tree is in a quiet park that serves as a bird sanctuary. A perfect place offering all that’s required for a pair of breeding ospreys. The birds usually mate for life. The eggs, mostly two to four, are incubated for 35–43 days. The typical lifespan of an osprey is seven to ten years.

Also called ‘fish hawks’, the osprey is well adapted for hunting fish, its main diet. A reversible outer toe helps it to carry fish while in flight, and the fish is always carried with its head facing forwards. Unable to dive to more than about three feet, ospreys gravitate towards shallow fishing grounds, where fish school near the surface. 

Caught on camera in Curaçao. Stopover sites, where migratory birds rest and refuel before continuing their journey, are vital. Photo: Els Kroon

The familiar osprey tweet is a wonderful welcome each time we open our backdoor and we immediately look up. Our encounter with ospreys began several years ago when we saw a busy couple gathering sticks, pieces of palm leaves, driftwood, turf and moss. For weeks we observed the action from up close. We noticed that both the male and the female contributed to the work and that they never retrieved a piece of nesting material accidentally dropped to the ground.

Ospreys usually build their nest in open surroundings for easy approach. They create a wide, sturdy base, safe from ground predators such as raccoons, in forks of trees or even on manmade platforms. Usually the male finds the site before the female arrives. He fetches most of the nesting material and she arranges it, often while vigorously fending off ospreys that encroach on their nesting area. In the first season the nest is relatively small, but they add to it year by year until it is large enough for a man to sit in.

Building a nest usually takes a month. The adult male can be distinguished from the female by its slimmer body and narrower wings. Ospreys usually mate for life. Photo: Els Kroon

In 2013 ‘our ospreys’ suffered a near fatal encounter when a fierce summer storm broke one of the branches supporting the nest and the nest, heavy from the rains, came down. One of the fledglings was hurt, but it was rescued by one of our neighbors who contacted a bird sanctuary. A month later the young osprey was returned to the site and released. The following spring a new nest was built in another tree, unfortunately out of sight, and our tree remained empty and silent, except of course for a large family of squirrels, a swarm of bees, many butterflies, frogs, crows, red cardinals and woodpeckers, who all call it home.

Two years on from the storm and, to our delight, ospreys were attempting to build a nest in the top branches of our old tree. History repeating itself and a new cycle of life begun.

An Osprey in San Francisco Bay, California. The raptor has a small portion of fish offal on its beak. Photo: Simon Carrasco/Wikipedia

This year marks the centennial of the 1918 Migratory Bird Treaty Act, the most powerful and important bird-protection law ever passed. Over the last century the law has saved millions of birds from depredatory human activities. National Geographic, Audubon and many more organizations joined forces to officially declare 2018 as the Year of the Bird organizing special themed events to run throughout the year.

The law was necessary to curb the excesses of the early 1900s when huge numbers of birds were killed simply for feathers to decorate hats. Countless more were killed by hunters for sport rather than food. Sadly, this law is now in peril.