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Osprey (Pandion haliaetus)

Prepared by Paul Nicholson, July 2022.

Left: The Osprey’s story since the middle of the 20th century is one we can learn from. Because of widespread use of DDT, Osprey populations plummeted. Following legislated bans of the insecticide, the species slowly recovered.

Right: The Osprey’s diet is almost exclusively fish. They are dramatic and effective when fishing. They will hover high above their target than go crashing into the water feet-first. They will catch a meal approximately once in every four attempts. All photos by PAUL NICHOLSON

The Osprey is a raptor that can be found across London. Interestingly, it is a bird that can also be seen across North America, South America, Europe, Asia, and Africa. One of the bird’s nicknames is Fish Hawk because it eats fish almost exclusively. Ospreys are large birds of prey. The wingspan of an adult is approximately 160 cm. They are identified by their wings that are crooked when in flight. They have a dark upperside, dark eye stripes, and a white cap. Like owls, Ospreys have a reversible outer toe that allows them to grip their prey with great dexterity.


The Osprey’s usual vocalization is a series of high-pitched chirps.


Listen to the Osprey’s vocalization below:


Ospreys’ nests are large and are often constructed on structures such as towers. The same nest is often refurbished and reused each spring.

Our Ospreys overwinter in the southern U.S., Mexico, or the Caribbean. They return to the London area in the last days of March and migrate south by early November. High nest-site fidelity is common among Ospreys. Nest are often refurbished and then reused in the spring. There are several active nests in London. The one on the third base light standard at Labatt Park near the forks of the Thames River can be easily viewed. Ric and Sandy Symmes have been Osprey Monitor Coordinators for Nature London for many years. Click here to review their comprehensive 2021 summary report on the city’s active nests.

Ospreys, like Bald Eagles and Peregrine Falcons, were among the species hit hardest by DDT. The insecticide was used widely across the agricultural sector through the middle of the 20th century and because it caused thinning of egg shells, breeding success plummeted. Rachel Carson’s 1962 book Silent Spring brought attention to the perils of the indiscriminate use of pesticides. By the 1970s, the U.S. and Canada had banned DDT and populations of Ospreys and other raptors slowly recovered. There were many lessons to be learned, not the least of which is that conservations measures can be successful. A greater threat to Ospreys today is entanglement in fishing line and other plastic line or twine that may be inadvertently incorporated in nests.

Help make London more Osprey friendly:

  • Don’t leave fishing line by rivers and ponds. If you find some, consider collecting and disposing of it.

  • Record Osprey sightings on the online eBird Canada platform that supports citizen science.

  • Avoid use of pesticides and reduce your ecological footprint as much as possible.


Learn more about the Osprey’s life history.

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